Issuu

Oct/ Nov 2026

MAZDA BT-50 Low-power drama

HOLDEN CAPTIVA Instruments and blower gone AWOL

HOLDEN CRUZE False oil warning

MAZDA 6 Current leak cuts action

Contents - TaT October/November 2026 - Magazine 113 4

Brendan Sorensen

Jeff Smit

Brendan Sorensen

The TaT Soapbox

Brake and clutch systems

Commanded does not mean flowing

Clinton Brett

Complete turbo diagnostics

Frank Massey

Exedy

Protex Parts

Frank meets with Tech Tina Premium driveline solutions Eighty new Protex caliper SKUs now available

Topdon

Expand your view of vehicle diagnosis

Jason Smith

DIY: You did what?

Jack Stepanian & Sam Nazarian

Walking the talk: How to check the calibration of the voltage axis of a DSO - Part 3

Gil Sher

When a rich code isn’t fuel

Permaseal

Simplifying sealant selection for today’s workshop

AAAA

Expanded EV rebates back independent workshops

Protex Parts

New boosters for two Aussie icons

GCG Turbos

Troubleshooting Hyundai iLoad D4CB turbocharger failure and replacement

ZF Aftermarket – TRW

Understanding brake shudder and the role of brake-disc design

Geoff Mutton

Are you ready for the repairs customers have been putting off?

Contributors

Clinton Brett

Frank Massey

Geoff Mutton

The Automotive Technician Pty Ltd publishes, in print and on its website, technical advice, case studies and items contributed by its members and readers for the purpose of educating technicians and preparing them for a rewarding aftermarket future. All advices are given in good faith, and are based on actual workshop repairs. No guarantee is given, nor any liability accepted in respect to any published advice. The Automotive Technician Pty Ltd is not responsible for the

Sam Nazarian

Jeff Smit

Jason Smith

accuracy of any information contained in material submitted by contributors or other third parties and published either in print or in digital format online and accepts no liability in relation to such materials or their content. Newsworthy articles or comments are welcomed, and should be submitted to the technical editor. All material appearing in The Automotive Technician is copyright. Reproduction in whole or in part is illegal without prior written consent from the Editorial board.

Brendan Sorensen

Jack Stepanian

TaT SD (Scan Data), TaT programs and TaT reviews are exclusive resources to financial members of the TaT network. All are strictly copyright and must not be published, copied or shared in any manner outside the TaT membership. All advertisers agree to indemnify the publisher for all damages or liabilities arising from their published or unpublished material.

The Automotive Technician 3

The TaT Team

The TaT Soapbox

Editorial Board Geoff Mutton Jeff Smit Technical Editor Jeff Smit Sub-Editor Cameron McGavin Scan Data Director Rod Maher Technical Research Brendan Sorensen Technical Contributors Brendan Sorensen Mark Rabone Frank Massey (UK) Jack Stepanian Sam Nazarian Jason Smith Clinton Brett (Diesel Help) Technical Assistance Team Deyan Barrie Andrew Kollosche Sideth Chiv Maurice Donovan Gil Sher Anthony Tydd Wayne Broady Jason Smith Marty Hosie Jack Stepanian Mark Rabone Rob Romano Daniel Armer Jack Mackay Gary O’Riain Scott Thomas George Anagnostoudis Associate Team Members Gary Homan Peter Hinds Columnists Geoff Mutton (TaT Biz) Advertising Enquiries Paul Woods, National Advertising Manager E: pwoods@tat.net.au Ph: 0494 044 958 Graphic Design Brigid Fraser E: production@tat.net.au PH: 0413 009 122 Affiliated Associations AAAA – info@aaaa.com.au Capricorn Society Alliance Supplier VASA – secretary@vasa.org.au

• TaT’s a fact • TaTassist • TaT Share • TaT train • Tat Biz • TaT SD (Scan Data) • TaT programs • TaT reviews • TaT check • TaT find are all trade names of The Automotive Technician Pty Ltd 4 The Automotive Technician

Brendan Sorensen

n the last Soapbox (TaT issue 112), Jeff Smit reflected on getting away from work and the value of a taking proper break. For me, however, the second half of 2026 has been moving in the other direction, with training and networking opportunities flowing almost back to back. It’s been busy but it has given me plenty to think about. When I wrote my Soapbox for TaT issue 111, Wire & Gas was still ahead of us. Automotive Air Conditioning, Electrical and Cooling Technicians of Australasia (VASA) and TaT had joined forces around the Better Together theme and I was looking forward to getting members, trainers and industry people into the same room. Wire & Gas 2026 gave TaT a full weekend in Brisbane to catch up with many members, share technical training and hear more about the policies and regulations shaping the work arriving in workshops. The formal sessions were valuable and so were the conversations between them. When technicians, workshop owners, suppliers and industry representatives have time to compare what they are seeing, we reach a point where we stop just complaining and start discussing what should be done about it. One of the highlights for me was presenting the inaugural TaT Industry Champion Award to David Ciccotelli from Bellbowrie Mechanical. David and his brother Chris have been TaT members for 10 years and during that time they have consistently represented what TaT was built around – technicians helping other technicians, sharing knowledge and wanting to see good workshops succeed. They are generous with what they know and support other workshops instead of treating everyone else as the competition. They have also built and run an outstanding workshop business here in Brisbane. The award was our way of recognising what David and Chris contribute to the industry and thanking them for the way they represent the spirit of TaT. Next on the calendar was the HSY Evolve Auto Festival in Melbourne, which brought a very different, distinctly European flavour. Overseas suppliers had the chance to put their latest wares and innovations in front of Australian technicians at the fantastically well-appointed Kangan Institute, with Cars & Coffee and an evening function running next door at the Fox Classic Car Collection. If you have not been through the Fox collection, all I can say is wow. It is well worth a look if you are in Melbourne. There is something for everyone, from the coachbuilding era through to the Formula 1-derived Mercedes-AMG ONE and its four electric motors. You can lose plenty of time in there; I found

myself admiring the bonnet badge on a 1930s Mercedes-Benz that looked like it would have taken one craftsmen a week to build. These events have all looked very different but the useful component has been the same – access to people prepared to explain what they have learned, put equipment in your hands and answer the awkward questions. This kind of exchange becomes even more valuable as the training becomes more specialised. As I write this, my next stop is Perth for the Australian Automotive Service Dealers Network’s (AASDN) Perth Automotive Training Event (PATE). By the time you read this, I should have delivered one of my favourite sessions, a full-day PicoScope 7 workshop, and debuted the full-day course on electrified vehicles that I have been working hard on this year. The course is designed to help technicians make the jump from previous training that focused more on identifying the components used on electrified vehicles – from 48V systems through to battery electric vehicles (BEVs) – to working through real diagnostic case studies. We have been gathering real-world tests, difficult diagnostic problems and the lessons that came from them through the EV & Hybrid Network. That real-world material is where the course is focused. It’s true that one course cannot make anyone ready to diagnose every electrified vehicle any more than attending one fuel-injection course made us ready for every fuel-system fault for the rest of our careers. Vehicle platforms, safety procedures, system strategies, failure patterns and test methods will keep developing. Lifelong learning is what we have all signed up for. I expect we will now see more targeted training in specific areas of electrified-vehicle diagnosis. This isn’t for the BEVs, this is for every second car that is rolling into the workshop now with a hybrid badge on the back or a 48V system. My hope is this course gives technicians a clearer starting point – what information to gather, what can be tested safely, what the evidence proves and where the limits of their current capability sit when one of these vehicles rolls through the door. I’m looking forward to finally putting this year’s work in front of a room full of technicians. From there, we will keep developing it and look at breaking the full-day course into a webinar series so members outside of the major cities and overseas can take part. Keep an eye out for those announcements.

Brake and clutch Jeff Smit

Brake and clutch systems: From mechanical hardware to intelligent safety control

rake and clutch systems were once largely self-contained mechanical systems. Today they are electronically managed parts of a vehicle-wide safety network, working alongside the anti-lock braking system (ABS), electronic stability control (ESC), autonomous emergency braking (AEB), adaptive cruise control (ACC) and electrified powertrains. For workshops and technicians, this transition changes both the faults likely to be encountered and the procedures required to diagnose and repair them correctly. There was a time when brake diagnosis began at the master cylinder and ended at the wheel cylinders or calipers. Clutch diagnosis generally involved checking pedal free play, hydraulics, the release bearing, pressure plate and friction disc. Those components remain important but modern brake and clutch systems can no longer be considered in isolation. Braking has become a vehicle motioncontrol function, while clutch operation is increasingly managed by transmission software and electric or hydraulic actuators. The mechanical components still create or transmit force but sensors, ECUs and software now influence when, where and how that force is applied.

From ABS to vehicle motion control

ABS represented the first major step towards electronically controlled braking. Wheel-speed sensors allowed the ABS control unit to detect an approaching wheel lock and regulate hydraulic pressure through solenoid valves and a return pump. ESC extended this capability. By comparing steering-wheel angle, wheel speeds, lateral acceleration and yaw rate, the system could determine whether the vehicle was following the driver’s intended path. It could then brake individual wheels and request a reduction in engine torque. Brake assist (BA), electronic traction control (ETC), electronic brakeforce distribution (EBD), hill-start assistance, hill-descent control and trailer-stability functions were subsequently built around the same network of sensors, controllers and hydraulic components. Australian Design Rules reflect this development. ADR 31 covers passengercar braking performance, ADR 88 specifies ESC, ADR 89 addresses BA systems and ADR 98 introduces requirements for AEB on passenger and light-commercial vehicles. As a result, the brake-control module is no longer activated only when the driver presses the pedal. It may receive braking requests from the ACC, automatic parking, ESC, hill-descent control, collisionavoidance systems or an automated-driving controller. AEB demonstrates this relationship clearly. A camera, radar or combination of sensors identifies a potential collision. The advanced driver-assist system (ADAS) controller assesses closing speed and the predicted vehicle path but it still relies on the conventional brakes, ABS, tyres and road grip to achieve the required deceleration. A fault that once affected only the ABS warning light may now disable the ACC, ESC and AEB at the same time.

The brake pedal becomes an electronic input

Traditional hydraulic systems use a direct connection between the brake pedal, booster and master cylinder. Modern electro-hydraulic systems can instead interpret pedal movement electronically 6 The Automotive Technician

and generate hydraulic pressure using an electrically powered actuator. Vacuum-independent boosters have become increasingly common because turbocharged engines, hybrids and electric vehicles (EVs) cannot always provide a dependable engine-vacuum supply. Integrated brake-control units go further by combining boosting, hydraulic pressure generation, ABS and ESC functions into one assembly. Brake-by-wire separates the driver’s pedal input from the mechanism generating the braking force. Pedal position and force sensors communicate the driver’s request to an electronic controller, while a pedal simulator provides the resistance and feel expected by the driver. Multiple electrical supplies, communication channels and braking actuators help ensure braking remains available if one component fails. Suppliers are developing electro-hydraulic, combined and fully electromechanical systems for increasingly automated vehicles. Electrification is accelerating this change. During light and moderate deceleration, a hybrid or EV uses its traction motor as a generator. The control system must continually blend regenerative braking with the conventional friction brakes while maintaining consistent pedal feel. The amount of regeneration available depends on battery state of charge (SoC), battery temperature, vehicle speed, motor capability and tyre grip. If the battery is full, cold or unable to accept sufficient energy, the friction brakes must provide a greater proportion of the deceleration. This happens automatically but it creates new maintenance considerations. Friction brakes may be used less often, particularly in urban driving, but that does not make

replacement. Some integrated brake units require scan-tool-controlled bleeding because air can remain trapped inside the hydraulic modulator. Technicians must use the correct brake-fluid specification and follow the manufacturer’s depressurisation procedure before opening an accumulatorequipped system.

After clutch, actuator, flywheel or dual-clutch repairs, the transmission may require clutch touch-point learning, actuator calibration or software adaptation. them maintenance-free. Reduced use can contribute to disc corrosion, glazing, seized slides and uneven pad contact. An EV may have substantial pad thickness remaining but still require brake repairs because of corrosion, contamination or poor contact between the pad and rotor.

The changing role of the clutch

The traditional driver-operated manual clutch is becoming less common in new passenger vehicles but clutch technology is not disappearing. It is moving inside automated transmissions and hybrid drive modules. Dual-clutch transmissions (DCTs) use two electronically or hydraulically operated clutches. One connects the engine to the odd-numbered gears and the other to the even-numbered gears. By preselecting the next ratio, the transmission can complete rapid clutch-to-clutch shifts with minimal interruption to drive torque. These systems depend on precise coordination between clutch pressure, engine torque, shaft speed and gear selection. Shudder, harsh engagement or delayed take-up may be caused by worn friction material but it may also result from actuator faults, incorrect adaptation, contaminated fluid, software issues or inaccurate sensor information.

The clutch is therefore becoming a powertrain-management device rather than simply a driver-operated coupling. Its operation may be coordinated with ETC, ESC, AEB, ACC and hybrid operating strategies. During an emergency-braking event, the transmission controller may reduce drive torque, open a clutch or change the hybrid operating mode while the brake controller builds hydraulic pressure.

What changes in the workshop?

Brake and clutch complaints must increasingly be treated as system-level problems. A full vehicle scan should be completed before components are removed or fault codes cleared. Relevant information may be stored in the ABS module, ADAS controller, transmission controller, hybridcontrol unit or central gateway. Wheel-speed sensors, magnetic encoder rings, steering-angle sensors, yaw sensors, brake-pressure sensors and pedal-position sensors must all be considered. A damaged wheel-bearing encoder, for example, may produce an ABS warning, unwanted ESC intervention, an AEB fault and ACC cancellation. Electronic parking brakes must be placed in the correct service mode before pad

ADAS calibration must also be considered. Wheel alignment, suspension repairs, rideheight changes, steering-angle sensor replacement, windscreen replacement and work involving cameras or radar units can affect the vehicle’s ability to recognise a hazard and apply the brakes correctly.

Replacement pads and rotors must match the specified dimensions, friction characteristics and thermal performance. Sophisticated safety software cannot compensate for unsuitable friction material, contaminated fluid, poor tyres or incorrectly installed components.

What comes next?

The likely progression is from conventional hydraulics to electro-hydraulic brakeby-wire, followed by semi-dry and fully electromechanical systems.

Semi-dry designs may retain hydraulic front brakes while using electromechanical rear brakes. Fully electromechanical systems could eventually eliminate brake fluid altogether.

Future vehicles may control braking force independently at each wheel, integrating braking, steering, suspension and powertrain torque through a central vehicle-motion controller. This will support automated driving while allowing manufacturers to tune pedal response and vehicle behaviour through software. The opportunity for workshops will remain substantial but the required skill set is changing. Tomorrow’s brake-andclutch technician will need to understand hydraulics, friction materials and mechanical wear as thoroughly as ever while also being comfortable with network diagnosis, software adaptation, ADAS calibration, hybrid operating strategies and high-voltage safety. The hardware has not become less important. It has become part of a much larger and more intelligent safety system.

The Automotive Technician 7

Cooling-system faults Brendan Sorensen

Commanded does not mean flowing

n electric coolant pump can answer a command and have its speed reported on the scan tool yet still fail to move useful coolant through the circuit that needs it. Proving circulation requires more than actuator status. Pump load, valve position and the movement of heat all have to agree. Late-model cooling-system faults can give us an impressive amount of information – requested and actual pump speed, valve position, several temperatures and a diagnostic trouble code (DTC) that appears to name the failed component. It is tempting to hear the pump, see actual speed follow the command and move on. Those readings establish control and rotational response. They do not establish that coolant is passing through the branch being assessed or transporting heat. The impeller may be turning in air, the wrong route may be selected, a branch may be isolated or a restriction or damaged impeller may be limiting flow. The diagnostic job is to combine electrical, mechanical, hydraulic and thermal evidence without asking one reading to prove too much.

Know the circuit state

A modern cooling diagram represents several possible circuits. Pumps, valves and heat exchangers may be connected differently during warm-up, cabin heating, transmission cooling, high engine load or a protection strategy. Volkswagen Group’s (VAG) third-generation EA888 system is a useful combustion-engine example. Its rotary-valve module can hold coolant static around parts of the engine, establish a small-volume circuit and then connect the radiator and other branches as operating conditions change. A pump can be healthy and spinning while a valve keeps the component under investigation outside the active coolant path. Before opening the data list, work out which pump should be running, which valve positions connect the branch, where heat enters and leaves and which sensors can show its movement. Then check what the active test actually controls. Some routines run the pump without placing every valve in the state needed for the test. Freeze-frame data and the conditions 8 The Automotive Technician

1. VAG EA888 cooling-system schematic.

reported by the customer may identify a circuit state that a short workshop warm-up will never reproduce.

Speed and load answer different questions

Many brushless coolant pumps contain their own power electronics. The engine or thermal-management controller may request a speed over local interconnect network (LIN) communication or pulsewidth modulation (PWM), while the pump reports actual speed and operating status.

Some pumps also use motor current and starting behaviour to recognise blockage or operation without coolant.

Requested speed tells us what the controller asked for and plausible actual speed shows the rotor responded. Current or calculated load indicates how hard the motor is working to hold that speed. That load figure only becomes useful when the pump size, supply voltage, command and circuit state are known. Pierburg’s automotive CWA coolant pumps are produced in 50W, 100W, 150W, 200W

2. VAG N488 transmission coolant-valve cutaway and flow path.

3. Expansion-tank vent hose and internal check-valve location. Note the arrow direction.

and 400W power classes. At 13.5V, those ratings equate to approximately 4A, 7A, 11A, 15A and 30A at rated electrical input. A Continental/VDO main coolant pump used across a range of BMW applications is specified at up to 36.9A at its nominal working point. This puts some scale around the current figures – 3-4A may be normal for a small auxiliary pump but very low for a large main pump commanded near full output. The application data still has to provide the real specification.

Some controllers also use motor-current feedback to assess pump load. On several General Motors applications, an onboard check runs the pump at roughly 4000RPM for 15 seconds and compares its alternatingcurrent feedback with a calibrated range. Low coolant or trapped air reduces that feedback. This can help identify an unloaded pump. Coolant movement through the branch needs separate proof.

At a fixed command, a liquid-filled pump should give repeatable speed and load while the expected temperature response develops downstream. Air at the pump can reduce load, and some systems will allow speed to rise towards an overspeed limit.

A mechanically jammed or dragging rotor is more likely to remain below requested speed, draw heavily or enter a restart or protection cycle. A closed valve or restricted heat exchanger is different again – the rotor may still reach speed and a centrifugal pump can draw less power as flow falls. Current and speed can separate an unloaded pump from a locked rotor but they cannot identify air, a closed route or a restriction without thermal evidence.

Build proof that coolant is moving

Use the information already available before adding test equipment. Graph requested and actual pump speed with any pump current or calculated-load parameter ID (PID) while commanding two or three steady speed steps. Actual speed, load and downstream temperature should change in a repeatable way.

Check supply and ground under load when the pump cannot follow the command, resets

or reports implausible data. Fit a current clamp only when load data is unavailable or suspect or when the pump circuit is already being accessed for those electrical checks. The external supply current should then be treated as a comparative trace because an internal PID may represent phase current or a calculated value. Then look for heat moving through the intended route. Begin from known starting conditions and graph the relevant temperatures while commanding the required circuit state. On the EA888, engine-coolant temperature sensor G62 and radiatoroutlet sensor G83 can help show whether heat has reached and moved through the radiator once that route is open. Contact probes or thermal imaging can extend the picture across a hose, cooler or heater core, provided the measurement points and test conditions stay consistent. Avoid chasing a universal inlet-to-outlet temperature difference. Heat input, flow rate, thermostat and valve position, fan operation, ambient conditions and sensor location all affect it. Look at the sequence and direction of change. If actual speed cannot follow the request after supply, ground and communication test correctly, focus on the pump and its control. On a system with load monitoring, high speed, unusually low current and no heat movement point towards air or another unloaded-pump condition. If speed and load look sensible but heat reaches the wrong branch, check valve position and routing. If the correct route is open but downstream temperature barely changes, check for trapped air, restriction or impeller damage and make sure the test had enough heat input and time. A static pressure test remains useful for checking leaks. It does not prove circulation, valve routing or successful de-aeration. Clearing a pump DTC after replacing a coolant component also leaves the repair unverified until the expected thermal response has been seen.

When the circuit has been opened

A system can appear full in the workshop even though one branch still contains air or

has not taken its full coolant volume. The reservoir may hold its level and the vehicle may idle normally while that branch remains closed. The shortage only becomes visible when a later operating state connects it to the rest of the system. The EA888 transmission-cooler branch demonstrates the problem. Its N488 valve keeps the branch isolated during part of warm-up and only admits flow within mapped temperature conditions. A short workshop warm-up may never fill it. When the valve opens on the road, that empty volume takes coolant from the common supply and displaces air. The reservoir can fall and another pump may ingest air even though the vehicle behaved normally in the bay. A valve stuck open can send coolant into a branch that should remain isolated during warm-up. The driver may notice weaker cabin heat or a temperature gauge sitting low, while some systems may set an under-temperature DTC and warning light. Compare the valve request with branch temperatures before blaming the main thermostat. Vacuum filling reduces the chance of trapped air but it does not cancel the vehicle-specific procedure. Depending on the system, the repair may require a component to be prefilled, particular valves to be opened, pumps to be run in sequence, a bleed routine to be repeated and the level to be rechecked after a defined drive and complete cooldown. Those steps deliberately open routes that normal workshop idling may leave closed. Many cooling systems use an internal nonreturn valve in a small vent hose near the expansion tank. The hose may carry an arrow showing the permitted flow direction. A restricted valve, a hose installed backwards or a replacement hose that omits the valve can prevent the circuit from venting and bleeding correctly. On systems that monitor pump load, air-related or overspeed DTCs may follow. It is easy to miss that valve when a damaged moulded hose is replaced with generic hose to get a vehicle moving late on a Friday afternoon. Matching the diameter is not enough when the original hose also controls flow direction. Check for arrows and one-way flow before substituting hose and preserve the valve’s direction and function. After any repair that opens a multi-branch circuit, reproduce the conditions needed to connect its less frequently used branches. Let the vehicle cool before the final level check, then repeat the relevant thermal or scan-data test. A quiet pump and a steady reservoir during the initial bleed are no longer enough to ensure the system truly is full and ready to be unleashed back into the wild. The Automotive Technician 9

ID and diagnostics Clinton Brett

Complete turbo diagnostics

etrol mechanics, by now you should have accepted that a diesel engine – whether a modern common-rail diesel (CRD) or an old-style mechanical system – operates with only fuel and air.

No spark is required to start and run a diesel engine. The difference in modern CRD is how the air and fuel reach the combustion chamber. You might have read my recent series of articles on fuel-control valves. Between the two (fuel and air), there appears to be more confusion about electronic fuel-component operation and function than about air control. When it comes to diagnostic process, they are equal. It’s not entirely the mechanic’s misdiagnosis. It’s a career change. It’s cheaper to replace the actuator than the entire turbo. Mechanics love to provide financial advice. They assume the car isn’t worth spending money on based on its age, their age, employment status, the clothes they wear and their attitude. I don’t want to spend much money but I want it fixed. It’s human nature to ask for a cheap fix but it’s not your job to provide financial advice, plus it’s illegal. I am experienced in the successful diagnostics of diesels. This month our business turned 13 and before I started Diesel Help Australia, my experience with turbo diagnostics was limited. After dealing with hundreds of case studies, and collaborations with our colleagues, I have a few alternative test methods I’ve been using for electronic pulse width modulation (PWM) actuators to take out the guesswork behind turbo diagnostics. I will cover a few of the many varieties. Our ever-growing technical-bulletin library includes dedicated bulletins for specific makes and models which also include the diagnostic trouble code (DTC) for the actual model engine/ECU. Some of these include Ford’s Ranger, Mazda’s BT-50 and Land Rover and Jeep models.

3. Vacuum-actuated turbo. 10 The Automotive Technician

One common and generic fault code is, P2263 – Turbocharger/supercharger boost performance. It’s a vague code that can be anything from a blocked exhaust-gas recirculation (EGR) cooler, stuck-open EGR valve or a turbo intake-pipe leaking. It can also be the turbo itself or the actuator.

Symptoms

The vehicle intermittently goes into limp mode, with the engine de-rating due to the P2263 fault code.

Failure/issue

Sticking/seized turbo actuator or internal turbo damage/failure. Most think it’s the actuator which fails and there are plenty out there guessing without thorough testing. After replacing only this actuator and not the entire turbo assembly, the vehicle leaves the workshop without a code but it doesn’t last. It’ll either return or the owner will be annoyed and you’ll never hear about it again until you read your Google reviews. How does an electronic component fail when it worked fine until now? We have done thorough testing to come to the conclusion that sticking variable-geometry turbo (VGT) vanes (pic 1) have been the most common cause. Read more to find out how not to misdiagnose the true cause of most turbo fault codes.

Diagnosis and/or early detection of the fault

Perform a visual inspection of the turbo inlet, outlet pipes and intercooler for excessive oil or air leaks. We advise smoke-testing the turbo-intake system. Remove the intake pipe at the front of the turbo and inspect the condition of the vanes. If the internal impeller vanes look OK (pic 2), investigate failed internal vanes of the VGT. These vanes can bind against the turbo housing, often due to excessive carbon build-up caused by exhaust gases passing through the turbine housing. This fault may occur more frequently depending on driving conditions. Vehicles that are used for short, stop-start trips, predominantly in city driving with extended idling, are more likely to experience

1. A turbo’s internal VGT vanes.

2. Impeller damage.

reduced turbo lifespan and an increased risk of premature failure with these types of turbos. Almost like your Bunnings car (TaT issue 112). Referring to the scan-tool data, it is possible to observe when the fault is occurring. This is only possible on turbos adapted with an electronic position sensor, which is not always an option on vacuum-operated turbo actuators. The image on this page is of a vacuumoperated turbo actuator fitted with an electronic position sensor (pic 3). Note the small vacuum feed tube is accompanied by an electronic harness. Check key-on/engine-off turbo actuator demand/command or desired versus actual/ measured position. Repeat the check again at idle and warm up the engine, driving under load and then returning to idle to recheck once the engine has become warm. Anything with a difference of more than 3.5 per cent is enough to trigger a fault. Some OEMs have greater tolerances but this depends on the strategy level being used in the ECU. Some examples of the scan tool data collected from cases:

4. Scan-tool data #1.

5. Scan-tool data #2.

6. Manifold absolute pressure (MAP) tester.

7. Worn actuator gear.

One case (pic 4) had an average difference of four per cent between desired and measured and as you’ll see in pic 5, a difference of five per cent. If you are still not satisfied with your findings on the scan tool, check the actuator arm for movement. When cold, remove the turbo arm away from the actuator and feel for freedom of movement. If there is any resistance when the turbo is cold, it will most likely be worse when warm. If the sticking is not present when the engine is cold, it is still vital to check when the engine is hot as this is when the fault commonly occurs.

tool to an analogue gauge such as Diesel Help Australia’s DPF & Turbo Boost Test Kit (pic 6).

Turbo-boost confirmation

Turbo-boost data varies across a broad range of specifications, so it is difficult to list all vehicles boost specs. We advise comparing the boost reading on the scan

Remember to take atmospheric pressure into account. Where applicable, deduct this from your scan-tool reading.

Electronic actuators only

For final confirmation, we advise performing a current-draw test. Locate the power supply for the turbo actuator and use an amp clamp, test cold and then hot. When warm the amperage increases, which is when failure occurs.

Check and compare the power supply to the turbo actuator. If the current draw is found to be more than 2A, this is an indication of the turbo failure. When checking for wear in the internal gears of the electronic actuator, there should not

be more than 3mm of free play (pic 7). On the mechanical section, the turbine housing, the arm should be free to move when disconnected from the turbo actuator.

Solution

Replace the entire turbo assembly. In our experience, it will help you avoid doubling your labour cost and time that will be difficult to claim back, not to mention your reputation. Well, that’s unless your supplier is going to cover your time wasted determining the cause.

Special notes

These turbo actuators rarely fail without the cause being the internal vanes grabbing the turbo housing. When fitted with electronic actuators, the actuator current is greatly increased when the vanes grab and this has often caused the complete failure of the actuator to a point where it no longer actuates. Vacuum-operated actuators can tear the internal rubber diaphragm, resulting in an inability to hold vacuum. • Find out more at dieselhelp.com.au

The Automotive Technician 11

Value diagnostics Frank Massey

Frank meets with Tech Tina

ollowing my initial visit to TaT’s AI diagnostic assistant Tech Tina, I committed to a full exploration of the diagnosis process for a 2019 Hyundai Kona 1.0 T-DGDI. The vehicle was presented to Eldon St Garage, the second all-marques garage in the Massey group. Like many similar vehicle-repair facilities, knowledge with diagnostics is always a challenge. With me having retired in February last year, diagnostics for the garage has become stressful, to say the least; they’ve often resorted to AI Frank, as was the case with the Kona. Baz from Eldon St Garage is a very experienced tech in his 40s and always keen to improve his diagnostic knowledge (big tick). He called me asking to look at an Audi TT with no throttle response and then also snuck in the Kona. Baz explained it ran rough from cold, improving as it warmed up, with DTCs relating to bank #1 lambda, misfire events and gasoline direct injection (GDI) railpressure control. Prior to my involvement, the oil and filter were replaced, complemented by a flush and new spark plugs. When I retired, I took all my tools home, including an unused full Pico kit which I am selling, as well as my compact Pico kit presented at my retirement. So I was down to my midwife kit – scope, digital multimeter (DMM), vac gauge, battery tester. Having been involved with Colin Bockman (TaT Membership Manager) trialling Tech Tina, I opted to help Baz implementing the online AI support program. I cheated a little – well, quite a lot actually.

1 12 The Automotive Technician

Diagnosing the problem prior to planning a Tech Tina session with Baz – with Baz present – we spent some time loading the basic evidence previously discovered from serial interrogation. This was my first ride, so it was wobbly. I was extremely interested in Tina’s response to a deliberately inexperienced input as I wanted to demonstrate the importance of accurate measured values, logical process and implementing AI support. I updated Tina that evening with some of the known values she had requested in her first response and diagnostic plan: • Smoke test the inlet, isolate the evaporative emissions control (EVAP) system, prove oxygen (O2) sensor plausibility, misfire monitors and monitor GDI rail pressure. From cold, she instructed me to check all temperature sensors, check European onboard diagnostics (EOBD) pending codes, clear codes and check the order of returning codes, as well as graphing rail pressure and verifying low fuel pressure. These are the values I gave back to Tina: A. Extended idle, hot engine • Short-term (ST) fuel adaption +4.6% • GDI target pressure 6.5 megapascals (mPa, 65 bar) actual 6.476mPa (64.7 bar) • Low-pressure target 400 kilopascals (kPa) (4 bar) actual 400.1kPa (4 bar) • Manifold absolute pressure (MAP) value too erratic to evaluate from numerical data only.

B. Elevated RPM, hot idle • ST fuel adaption +0.422% • GDI target pressure 14mPa (140 bar) actual 14.008mPa (140 bar) MAP value 20 inches of Mercury (inHg) (350 milllibars [mb]) Fault codes P0191 – Rail pressure range performance P0171 – System lean bank 1 (first code to return) P0195 – O2 sensor extended lean shift (second code to return) I arranged to return the following day for a structured training session based on the test plan presented by Tina. From cold, we conducted a battery conductance test = 85 per cent. All temperature sensors showed 21ºC. While not mentioned by Tina, we confirmed adequate fuel level. We then data-logged the MAP sensor, target rail pressure, actual rail pressure, target low pressure and actual low pressure. Pic 1 was taken immediately after cold start. Note the GDI pressure has perfect symmetry – I will discuss the actual value later. The differential is due to the absolute target value.

The elephant in the room is mapping performance. High values represent extremely poor intake pressures, just below atmospheric value (poor vacuum), followed by a sudden recovery to 295mb (much improved intake vacuum). Also note five sudden upward peaks reaching atmospheric value (no vacuum). Fuel pressure starts at approximately 140 bar, dropping to approximately 6.5 bar. Pic 2 was taken while still cold with erratic idle and almost stalling. GDI pressure is unstable, causing the P0191 DTC, symptomatic not problematic, certainly caused by the elephant in the room. I am suggesting the look-up table (fuel-mapping software) is confused, searching for a value sufficient to stabilise the engine. MAP values are up and down like a bride’s nighty – here is the problem. Is the surging causing the erratic MAP value or is the MAP irregularity causing the surging? I am hoping you have focused on the sudden spikes in the graphed MAP value. Here is the critical issue. This was not obvious when observing digital data values only. One lesson I have never forgotten from

experience – tech doesn’t always trump simple tools.

Out comes the vacuum gauge. I mentioned cheating, and quite a lot, I had used the gauge on my initial investigation. I did not initially share this with Baz as I wanted him to explore Tech Tina and gain the confidence of a structured approach.

Pic 3 shows the vacuum gauge’s black needle displaying exceptionally low vacuum. Note the exceptionally low intake vacuum (pressure differential below atmosphere) with the black needle sweeping between 5inHg and 10inHg. The gauge is deliberately

not glycerine damped to avoid missing this level of erratic detail. Nominal value 20inHg and stable, as was the case at elevated throttle. The primary problem is mechanical – sticking valves or tappet jacking, especially when cold.

An interesting thought here – GDI does not deliver fuel behind a closed inlet valve. It does, however, recirculate exhaust-gas recirculation (EGR) gases. Therefore valve-stem deposits may be contributing to the fault. I hope you enjoyed the topic and promise not to bend the rules so much on a second date with Tina.

The Automotive Technician 13

Premium driveline solutions E xedy is a trusted name in Australia’s automotive aftermarket when it comes to delivering premium driveline solutions.

Backed by a legacy of innovation, quality and reliability, Exedy clutches have become synonymous with performance, whether operating a heavy-duty diesel workhorse or a performance-modified street car.

Exedy Australia knows professional mechanics and workshops demand parts that not only fit perfectly the first time but perform under the toughest conditions.

The brand’s extensive range of clutch solutions covers everything from daily drivers to highperformance and heavy-duty applications and includes: • • • • • • •

OEM Replacement Clutches: For reliable, factory-spec performance Sports Tuff: Designed for enhanced street performance Ballistic Tuff: Designed for aggressive and enhanced street performance and competition Devil Clutch: Performance-focused for serious racers Racing Clutch: Engineered for track performance and quick engagement Safari Tuff: Ideal for 4x4 and touring applications Truck Tuff: Heavy-duty solutions for commercial-transport vehicles

14 The Automotive Technician

•

Safari Extra Tuff: Built for 4x4 vehicles operating in extreme conditions • Agri Tuff: Tailored for agricultural and farming machinery This broad selection ensures that no matter the vehicle, the terrain or the application, Exedy has a clutch solution that fits

Now stocking a range of quality brake drums

To further support workshops and mechanics, Exedy Australia now stocks a range of quality brake drums, available for immediate purchase through its nationwide distribution network. Backed by the brand’s commitment to quality, these brake drums are engineered to deliver smooth, consistent braking performance and excellent durability in Australian driving conditions. The range covers many popular diesel and commercial vehicles, including: • Toyota HiLux (254mm and 295mm variants) • Mitsubishi Triton (2006-on) • Ford Ranger, Mazda BT-50 and Ford Courier (1999–2022) • Isuzu D-Max, Holden Colorado and Rodeo

•

Toyota Hiace, Hyundai Getz, Suzuki Swift and more Each unit is precision-machined and qualityinspected to ensure correct fit and performance for your customers.

More than just clutches

With more than 60 years of global experience and decades of support for the Australian market, Exedy continues to evolve to meet the needs of modern workshops. The brand’s expanding product range – now including clutches, brake rotors and drums, Aisin cooling and brake-and-clutch hydraulics and 555 steering components — reflects its commitment to being a comprehensive, reliable partner to the trade. • To find out more or place an order, contact Exedy Australia on 1300 366 592, email sales@exedy.com.au or go to exedy.com.au

Eighty new Protex caliper SKUs now available

eeping vehicles safely on the road starts with having the right parts available when workshops need them.

That’s why Protex has expanded its caliper range with 80 new stock-keeping units (SKUs), delivering broader vehicle coverage across passenger, 4WD and commercial applications. This latest expansion strengthens the Protex braking portfolio, making it easier to source quality replacement calipers and support a wider range of repair requirements.

Why this matters for workshops • • • • •

Broader vehicle coverage across popular Australian applications More options when sourcing replacement brake calipers Support for complete braking solutions from a single supplier Reduced sourcing challenges with a wider range available through Protex Helps get vehicles back on the road faster

More than just a caliper

The expanded range forms part of the complete Protex braking solution, allowing workshops to source everything they need for a comprehensive brake repair.

With Protex, customers can source: • Brake calipers • Brake rotors • Brake pads • Hydraulic components • Wheel bearings and hubs This creates a one-stop braking solution that can help simplify ordering, reduce downtime and improve workshop efficiency.

Why Protex?

Protex has been trusted by the Australian aftermarket to deliver reliable braking solutions backed by strong vehicle coverage and consistent quality for more than 25 years. Whether servicing everyday passenger vehicles, hard-working commercial fleets or growing 4WD applications, Protex continues to invest in range expansion to help meet market demand. Explore the expanded Protex caliper range and discover more options for a complete braking solution. • Find out more at protexparts.com.au or call 03 8369 1400

The Automotive Technician 17

Expand your view of vehicle diagnosis

odern vehicle faults are rarely solved by a single test. In cooling systems, brakes and clutches, symptoms can point to multiple possible causes, making efficient diagnosis and fault verification essential. TOPDON brings together two complementary tools to help technicians move from identifying a problem to narrowing down where to investigate.

ONE Pro: Deeper diagnostics for complex faults

The TOPDON ONE Pro is built for technicians who need more than a basic fault-code scan. Its Multi-Channel QuickScan function can scan multiple vehicle systems simultaneously, while Live Data Fusion brings related data streams together for easier comparison. Bidirectional controls allow technicians to actively test

vehicle components where supported, helping confirm whether a suspected system or component is responding as expected. Coding and programming functions support module configuration and software-related procedures. OE topology provides a visual view of vehicle networks, helping technicians understand system relationships and trace faults more efficiently. Support for accessories such as battery testers, oscilloscopes and borescopes can also extend the ONE Pro into a broader testing workflow.

TC004 Lite: See abnormal heat before disassembly

Not every fault is obvious from diagnostic data alone. The TOPDON TC004 Lite adds a thermal perspective, allowing technicians to visualise abnormal temperature patterns before taking components apart. Whether checking temperature distribution across cooling-system components or comparing heat around brake or clutch components, thermal imaging can help identify areas that warrant closer inspection. Its 160 × 120 thermal resolution is enhanced to 320 × 240 with TOPDON’s Thermal

18 The Automotive Technician

Imaging Super Resolution (TISR) technology, while dual thermal and visible-light cameras provide additional visual context. With up to 21 hours of operating time, the TC004 Lite is suited to extended workshop use. Thermal images can also be analysed through TopInfrared and TopView software. By combining electronic diagnostics with thermal inspection, technicians can gather more information before committing to disassembly. ONE Pro helps investigate what the vehicle’s systems are reporting, while TC004 Lite helps reveal what is happening through heat, giving workshops another way to pinpoint problems and verify their findings. • Find out more at au.topdon.com or call 07 5625 3501

HOLJH13116

Holden Cruze (JH) 2013, 168,797km Four-cylinder

Customer complaint

The engine-oil warning light was illuminated. It had first started intermittently but now stayed on all the time. The owner’s mechanic had checked the oil level and replaced the oil-pressure switch but this did not solve the problem.

Problem summary

Verified the customer’s complaint about the oil light on the dashboard.

Diagnostic sequence

Started with the usual diagnostic checks, including load-testing the battery, checking charging-system operation and carrying out an all-lights test. System research using a wiring diagram showed the oil-pressure switch wire runs to the powertrain control module (PCM) on the yellow wire. Connected the scope to the wire at the harness above the switch as the switch is difficult to access. With key on, engine off (KOEO), it showed zero volts as expected but after starting the engine the scope showed fluctuating voltage of approximately 3V to 8V. There was some variation in this voltage when manipulating the wiring harness, more so closer to the PCM. Removed the PCM harness connectors and found coolant in one plug and associated corrosion on the pins (pic 1 and 2). Traced the coolant leak back to the thermostat heater. The coolant was migrating through the wires to the PCM (pic 3).

Fault description

Corrosion at the PCM harness connector due to a leaking thermostat heater and coolant migrating through the wires. This corrosion path was pulling the oilpressure circuit bypass voltage down enough to trigger the oil light on the dashboard.

Fault solution

Removed the PCM, then cleaned and treated the pins and harness terminals as thoroughly as possible. Removed and replaced the thermostat assembly and housing. Reassembled all components and confirmed the problem was solved.

Recommended time

Diagnostic time was 90 minutes, taking into account preparation and research. Repair time was three hours, taking into account the location of parts and carrying out the repair to a tested outcome.

Repair solution by TaT Tech Team member Marty Hosie.

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HOLCG18430

Holden Captiva (CG) 2018, 175,243km Four-cylinder

Customer complaint

The instrument cluster (IPC) and blower fan would intermittently stop operating while driving.

Problem summary

Verified the concern. After around 10 minutes of driving or idling, the instrument cluster would go completely black with no backlighting, no gauge operation and no display (pic 1). At the same time, the blower fan would stop operating. Both systems would return to normal after about one minute.

Diagnostic sequence

Checked the battery voltage and charging voltage first and found they were normal at 12.5V and 13.9V respectively. A scan of the vehicle uncovered the following relevant fault codes: •

U0155 – Lost communication with the instrument panel cluster

•

B1325 – Control module power circuit

Checked all fuses and found they were okay.

When the blower fan stopped operating, the climate-control functions still appeared on the centre display and the blower speed command could still be adjusted, indicating the control side was still functioning even though the fan had stopped. Carried out circuit tracing and wiring diagram checks on both the instrument cluster and blower-fan power supplies. Relay checks showed that removing the run relay stopped the blower fan, while removing the run/crank relay removed power to the instrument-cluster fuse.

Further testing showed the IPC was staying powered by its battery supply rather than losing its ignition supply.

2 Removed the instrument cluster and backprobed the ignition and battery circuits. While the fault was being monitored, the battery feed to the IPC dropped from 12.5V to 2.2V when the failure occurred (pic 2), at which point the IPC switched off and the blower fan also stopped. Further investigation confirmed the IPC battery supply originated from the enginebay fuse box. Flexing the fuse box caused the IPC battery-supply voltage to change slightly, confirming an internal connection issue.

Removed the top section of the fuse box for inspection. The fuse box connectors are retained by three large bolts and found the centre retaining bolt was loose (pic 3). When the bolt was tightened, the IPC battery supply immediately returned to 12.5V.

Fault description

The centre retaining bolt for the engine-bay fuse box connector had loosened, causing a voltage drop on the battery-feed circuit supplying the instrument cluster and other affected components. This voltage drop had caused the IPC to shut down and the blower fan to stop operating intermittently.

Fault solution

Secured the three fuse-box connector retaining bolts and inspected the connectors for damage – they were undamaged.

Recommended time

Diagnostic time was 90 minutes, taking into account preparation and research. Repair time was 10 minutes, taking into account the location of parts and carrying out the repair to a tested outcome.

3 22 The Automotive Technician

Repair solution by TaT Tech Team member Gary O’Riain.

MAZUN09128

Mazda BT-50 (UN) 2009, 337,782km Four-cylinder

Customer complaint

The malfunction indicator light (MIL) was on and the vehicle had a significant lack of power. Its service and repair history were unknown.

Problem summary

The vehicle was operating in a reducedpower mode. Initial checks showed the engine had oil and coolant, the battery and charging system were okay and there were signs the transmission had previously been replaced with a used unit. Although a crankshaft-related fault code was initially stored, the confirmed cause of the reduced-power condition was an open-circuit intake-shutter solenoid valve controlling the throttle-body butterfly.

Diagnostic sequence

Tested the battery and charging system and they were okay. Checked the fluid levels and while the engine oil was dirty it was acceptable for the immediate diagnosis. Carried out a full vehicle scan with an Autel scan tool and initially found two ECU fault codes, P0663 and P0335. Road-tested the vehicle with scan data recorded and it was clearly in a limp or reduced-power mode. At full acceleratorpedal position, the engine speed only reached about 2200RPM and road speed was limited to about 55km/h, while fuel-rail pressure was around 15,000psi. This was supported by the recorded scan data (pic 1). Cleared the fault codes and P0663 returned immediately with the key on and engine off, indicating a circuit fault. P0335 did not return and was treated as unrelated to the confirmed fault.

1 The scan tool described P0663 as an intakemanifold tuning valve (IMTV) control circuit open for bank #2. Because similar codes on some petrol Mazda engines often have little effect on driveability, we initially considered the code less likely to be the main cause. Carried out further checks to verify injector coding, confirm the turbocharger was not seized and inspect the throttle body.

Before dismantling further, carried out some research through TaT and the OE workshop information. This confirmed the correct OE description for P0663 was Intake shutter solenoid valve full control circuit open rather than the scan tool wording.

Further investigation of the OE wiring diagram identified the relevant solenoid as the vacuumcontrol solenoid for the throttle-body butterfly, mounted beneath the intake manifold. Disconnected the solenoid and substituted a 0.5A test bulb in its place. This proved the power and ground to the circuit were good, the ECU could control the circuit correctly and the ECU would not reset the code with a proper electrical load present. Next, tested the suspect solenoid with a digital multimeter and found it to be open circuit, confirming the fault (pic 2).

Ordered a replacement solenoid pack and bench-tested the new unit prior to installation, which showed correct resistance (pic 3). Fitted the new solenoid and road-tested the vehicle again with data monitoring. Engine performance had returned to normal and the fault was resolved.

Fault description

The intake-shutter solenoid valve for the throttle-body butterfly control had failed open circuit. This prevented proper control of the intake-shutter system, causing the ECU to log P0663 and place the vehicle into a reduced-power mode.

Fault solution

Replaced the faulty intake-shutter solenoidvalve assembly, cleared the fault code and confirmed via a road test that full engine performance had returned and the reducedpower condition was no longer present.

Recommended time

Diagnostic time was three hours, taking into account preparation and research. Repair time was two hours, taking into account the location of parts and carrying out the repair to a tested outcome.

Tips for TaT

This shows that prior knowledge can sometimes lead you astray. Checking the OE manual if available and doing research is key. Also, do not believe everything your scan tool is telling you – sometimes it is blatantly lying. Repair solution by TaT member Theo van de Steeg. The Automotive Technician 23

MAZGH10447

Mazda6 (GH) 2010, 149,246km Four-cylinder

Customer complaint

The vehicle would start when jump-started but would not restart if the ignition was cycled. After switching the ignition off and attempting to restart, there were no dash lights and the engine would not start.

Problem summary

The customer stated the battery was around a year old. The initial battery voltage was 1.1V. Jump-started the vehicle and checked the charging-system output at 13.8V, confirming the alternator was charging. The battery tested faulty and required replacement before further diagnosis could continue.

Diagnostic sequence

The customer supplied and fitted a replacement battery. Battery voltage was then 12.6V and the charging-system output was 14.1V. Successfully carried out a steering-angle reset and the warning lights and related diagnostic trouble codes (DTCs) cleared after the steering was turned to full lock left and full lock right. With the battery and charging system operating correctly, carried out a parasitic current-draw test. The current draw measured 187 milliamps (mA) after 10 minutes, which was excessive and capable of flattening the battery (pic 1). Checked the fuses to locate the cause of the draw and found corrosion in the interior fuse box and related connector area (pic 2). Removed the interior fuse-box fuses and body-control module (BCM) connectors. Removed and inspected the BCM and

1 found no corrosion on the BCM circuit board. but corrosion was present at the fuse-box connector area (pic 3).

Fault description

Corrosion in the interior fuse box and connector area was causing current leakage between circuits, resulting in excessive parasitic current draw and a flat battery.

Fault solution

Cleaned the affected connectors and fuse holders, then applied dielectric grease and refitted all components.

2 Rechecked the parasitic current draw and it measured 44mA after 10 minutes, confirming the repair had reduced the draw to an acceptable level (pic 4).

Recommended time

Diagnostic time was 50 minutes, taking into account preparation and research. Repair time was 20 minutes, taking into account the location of parts and carrying out the repair to a tested outcome.

Tips for TaT

The corrosion was most likely related to a previous blocked sunroof concern reported by the customer. When diagnosing a flat battery on this model, inspect the interior fuse box and connector area for moisture ingress or corrosion, especially where there is a history of sunroof drain issues or previous water entry. I suspect the battery initially went flat possibly due to the corrosion or having spent more than a month having smash repairs performed on it – I have seen repairers leave doors open, lights on, etc. Repair solution by TaT Tech Team member Gary O’Riain.

3 24 The Automotive Technician

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Electrical faults Jason Smith

DIY: You did what? W

ith sales of hybrid and electric vehicles (EVs) in Australia increasing, I’m now starting to find increasingly unusual or intermittent electrical faults with vehicles. Don’t worry, this isn’t another highly technical article that may be difficult to understand. Rather, I’ll be highlighting a case study where a customer checked out a YouTube video and had a go himself, then did something I’ve never seen in almost 40 years in this industry. I’ll also briefly be handing over the reins to David Bourke from GET Electronic (getelectronic.com.au), who explains the correct use of dielectric grease. But first, the case study.

The car

Lexus RX400h (MHU38R), 2008, 3MZ-FE 3.3-litre V6, approximately 100,000km on the clock (pic 1).

The complaint

The car would stop intermittently, maybe once a month. The customer would pull over, cycle the key off then on and then the car would start straight up and go for another month. During the information gathering and customer-interview stage, the customer told me some alarming things that I am hearing more and more from hybrid and EV customers. The customer said he’d been researching the problem himself and bought himself a mini scan tool or code reader. When the car would fault, he would plug in his scan tool

2 26 The Automotive Technician

1 and read the diagnostic trouble code (DTC), U029A – Lost communication with hybrid battery pack sensor module. He’d then clear it and away he’d go. I told him this was not a good idea. I said by clearing the DTC he was also clearing any valuable freeze-frame data (i.e. the computer taking a selfie of the data when the fault occurred) and possibly clearing any manufacturer’s subcodes (the -00 numbers or letters after the four digits of the DTC). At this point, I was ready to bail out of anything to do with this job but the customer said he’d found me via the EV & Hybrid Network and acknowledged that we were leaders in this field. He seemed like a nice fella and seemed ready to listen and co-operate. My schedule was busy but he agreed to a booking in about six weeks’ time. To my shock and amazement, however, when he arrived six weeks later I discovered he’d been at it again. This is where it gets interesting. The customer told me he’d come across a YouTube video showing the problem to be in a wiring-plug connector in the B-pillar in the left-front kick panel. He revealed that just a few days before he’d pulled the kick panel off, disconnected some of the wiringplug connectors and sprayed silicone spray in there. I’ll repeat that – silicone spray. Now this was something I’d never heard of, so I kindly suggested it maybe wasn’t a good idea for me to look at the car because he seemed to want to fix it himself. He pleaded with me to take the job on, so against my better judgement and after listing some very firm rules I agreed to perform level one or two diagnostics on the car only, with no guarantees of a find or fix.

Diagnostics

Like any diagnostic job, I did my preparation and research prior to the vehicle arriving (i.e.

trade portals, Technical Service Bulletins [TSBs] and the TaT website).

Next came a road test and then what a call a ‘work-up’ – I checked all lights, performed a smart test (12V) on the battery and charging system and checked and corrected underbonnet levels, as well as performing visual checks of components and electricals, plus a fuse check I found the coolant was a little low, so added 1.5 litres (pic 2). The brake fluid (pic 3) and engine oil were in poor condition, which I reported before moving on.

I performed a full diagnostic scan of all modules and found four DTCs in three different modules, none of which I believed were related to the problem, so I noted, captured and stored them.

Importantly, the unverified U029A code previously mentioned by the owner was not present in the hybrid control module.

I observed freeze-frame data and roadtested the vehicle again while monitoring numerous data parameter IDs (PIDs) in numerous modules – no faults were present and nothing stood out. I checked the trade portals again and the TaT website, which led me to one possible Repair solution involving a similar fault in

The repair

I removed the left-front kick panel for further inspection and found no signs of recent water ingress. I did, however, see evidence of silicone spray and one wiring-connector plug with a damaged retainer (pic 4) – I believe this was one of the connectors the customer had removed. Unfortunately, I had to unplug numerous connectors to inspect further, something no technicians likes to do as it can create another issue or inadvertently fix the problem. After removing most of the connectors, I found the one with the damaged tab had a small amount of green corrosion within it (pic 5). I cleaned it with a toothbrush, contact cleaner and compressed air. I used the contact cleaner again to remove any traces of silicone spray that had been used by the owner on the other connectors, then checked the pin tension and used a small, sparing amount of dielectric grease (pic 6) on some of the connectors to help resist any further corrosion. Let’s take a break and discuss dielectric grease and its correct use – this is where I’ll hand over to David Bourke.

Dielectric grease: Where it works and where it doesn’t

5 a similar car. In this case study, there was possible corrosion in the wiring inside the left-front kick panel. It was time for more research. My basic understanding of how the system works is there is a module within the high-voltage (HV) battery pack. This communicates with another module in or near the left-front kick panel. The wiring and connectors in between go via that left-front kick panel. This was potentially worth investigating if it indeed related to the fault code U029A, so I called the customer for further discussions. Long story short, he wanted me to fix his silicone-spray dilemma – I made no guarantees or promises but did give him a price estimate and agreed to the job.

Dielectric grease has become a much more common topic of discussion lately, particularly when dealing with waterdamaged modules. The most common question is pretty simple – is it useful or harmful? However, the answer, like most things in electronics, depends entirely on the application. At its core, dielectric grease is designed to prevent moisture ingress. Applied correctly, it can protect connectors from water, oxygen and contaminants that lead to corrosion. However, it is important to remember that dielectric grease is also an insulator. If overapplied, especially in low-voltage (LV) systems, it can interfere with the very electrical connection you are trying to protect. In a typical 12V automotive application, filling a connector with grease in an attempt to fix an intermittent fault is rarely effective. By the time a connection becomes intermittent due to water ingress, the damage has already occurred, usually in the form of corrosion or electrolysis.

Adding grease at this stage does not reverse the issue – it often complicates diagnostics for the next technician by masking the root cause and creating unnecessary mess. HV applications present a completely different scenario. Dielectric grease is commonly used on ignition-coil boots, X-ray tube couplers and other HV interfaces. In these environments, which range from 10 kilovolts (kV) in ignition systems up to 80kV or more in X-ray equipment, moisture and surface contamination can lead to arc tracking. At higher voltages, electrical leakage across contaminated surfaces becomes significantly more likely, making moisture exclusion critical. Here, dielectric grease serves an essential role in maintaining insulation integrity. In conclusion, dielectric grease is a powerful tool when used appropriately. In LV systems, it should be applied sparingly and primarily as a preventative measure, not as a fix for existing faults. In HV or harsh environmental conditions, however, it becomes a critical part of ensuring longterm reliability. As always, proper diagnosis and preparation remain the most important steps in achieving a lasting repair.

The repair (continued)

Now back the Lexus, which was reassembled and road-tested with no faults or DTCs present. I returned the vehicle to the owner with no guarantee of a find or fix and he was happy with my efforts. I contacted him a few months later and he said the car was still OK. Sometime later, however, the same or another problem developed. I researched further which pointed to a fair bit of diagnostic time and no guarantee of reliable repeatable fault. The customer decided not to go any further. In closing, this probably wasn’t a good job for a workshop to take on as the problem was not reliably repeatable and I knew the customer had been fiddling around with the car. However, he was a nice person and did agree to all my terms, conditions and charges, so sometimes things do work out. Regarding dielectric grease, I’ve noticed when I buy good-quality replacement coilon-plug (COP) ignition coils, they come with a small amount of dielectric grease inside the boots. This is to keep the high kV in and the contaminants out. The takeaway from this – use dielectric grease sparingly, only as an insulator, not a conductor. Happy diagnosing. The Automotive Technician 27

Electric cars Sam Nazarian

Jack Stepanian

Walking the talk: How to check the calibration of the voltage axis of a DSO Part 3

technician’s diagnostic pathway can sometimes become blurred by inaccuracies in the signal or waveform being measured. When analysing automotive waveforms such as controller area network (CAN bus) communication signals, sensor outputs or actuator control signals, the accuracy of the oscilloscope becomes critical (pic 1a and 1b). Modern vehicle systems often operate with relatively small voltage changes. An incorrect voltage display can lead the technician towards an incorrect diagnosis, resulting in unnecessary component replacement, wasted labour and customer dissatisfaction. For this reason, the accuracy of the oscilloscope’s vertical voltage scale (Y axis) is of paramount importance. Most standalone oscilloscopes include a built-in calibration-output terminal that provides a known reference waveform (see TaT issue 112, page 26).

2 28 The Automotive Technician

1 However, many modern automotive scan tools and portable oscilloscopes do not include this feature. So from a mechanic’s point of view (MPOV), what practical method can be used to perform a quick check of oscilloscope voltage accuracy? One simple solution is to use commonly available batteries as a practical voltage reference source.

Adjusting the voltage scale (Y axis) The Y axis of an oscilloscope represents the amplitude, or size, of the measured voltage signal. Accurate Y-axis calibration is essential because every voltage measurement displayed on the screen is based on this scale. The method of adjusting the sensitivity of the Y-axis, commonly referred to as the volts per division (V/div) setting, varies between oscilloscope manufacturers and models. For the digital storage oscilloscope (DSO) used in this example, the procedure is straightforward (pic 2). Simply tap the touch-sensitive screen (pic 2a) to access the channel-control menu (pic 2c). From this menu, the desired channel can be switched on or off. The Y-axis sensitivity can then be adjusted by tapping the channel-settings button (pic 2b) and selecting the required V/div value (pic 2d). As the selected V/div value changes, the oscilloscope automatically rescales the

waveform display, allowing both small and large voltage signals to be viewed clearly.

But how accurate is the displayed voltage scale? Like any measuring instrument, an oscilloscope can drift out of calibration due to age, component tolerances, environmental conditions or accidental damage. Before relying on a waveform for diagnosis, it is good measurement practice to verify that the displayed voltage is reasonably accurate.

Verifying the voltage scale

To verify the accuracy of the Y axis, a known voltage reference is required.

A professional calibration laboratory would normally use precision voltage references or regulated laboratory power supplies. However, for workshop-verification purposes, a battery with a known and stable voltage can provide a practical alternative. For example: • A 1.5V battery can be used when checking lower voltage ranges such as 500 millivolts per division (mV/div) or 1V/div •

A 9V battery can be used when checking higher voltage ranges such as 5V/div

Before using any battery as a reference source, its actual voltage should first be measured using a reliable digital multimeter (DMM).

Although batteries may carry similar voltage ratings, their discharge characteristics differ considerably depending on their chemistry.

3 Choosing a suitable 1.5V reference source

Common 1.5V batteries include: • Carbon-zinc • Rechargeable nickel-metal hydride (NiMH) • Rechargeable 1.5V lithium-ion Although these batteries may share a similar voltage rating, they behave very differently during discharge (pic 3). A carbon-zinc battery may initially measure approximately 1.55V when new. However, as the battery ages and its internal resistance increases (see TaT issue 79, page 32-33) the voltage gradually falls. Consequently, it is not the most reliable choice as a voltage reference (pic 3a). A NiMH rechargeable battery behaves differently. Even though its open-circuit voltage may only be around 1.3V, it can still be fully charged and capable of delivering substantial current. This highlights an important diagnostic principle – opencircuit voltage alone does not always indicate battery condition (pic 3b). Rechargeable 1.5V lithium batteries offer a different approach. Internally, they contain a lithium-ion cell and electronic-regulation circuitry that maintains a nearly constant 1.5V output throughout most of the discharge cycle (pic 3c). Because of this regulated output, the battery voltage remains remarkably stable until the internal-protection circuit disconnects the battery at the end of its usable charge. This characteristic makes regulated lithium batteries particularly suitable as practical oscilloscope voltage references.

Checking higher voltage ranges using 9V batteries

The same principles apply when checking higher oscilloscope voltage ranges. A fresh carbon-zinc 9V battery may measure approximately 9.3-9.6V when new. As the battery discharges, the voltage gradually decreases (pic 4a). A NiMH 9V battery normally consists of

several NiMH cells connected in series. Depending on the internal construction, nominal voltage may be approximately 8.4V or 9.6V. These batteries generally maintain their voltage reasonably well throughout most of their discharge cycle (pic 4b). Many modern rechargeable lithium 9V batteries contain internal electronic regulation. As a result, the output remains close to 9V for most of the battery’s operating life before switching off rapidly once the minimum safe internal-cell voltage is reached. This stable output characteristic makes regulated lithium 9V batteries an excellent practical reference source for checking higher oscilloscope voltage ranges (pic 4c).

Practical recommendations (MPOV) For technicians wishing to perform a quick workshop verification of oscilloscope voltage accuracy: Best low-voltage reference: • A regulated rechargeable 1.5V lithium battery Alternative: • A fully charged NiMH rechargeable battery Best higher-voltage reference: • A regulated rechargeable lithium 9V battery In all cases, verify the actual battery voltage with a DMM before using it as a reference source. It should also be remembered that the objective is not laboratory-grade calibration. Rather, it is to confirm that the oscilloscope is displaying a reasonably accurate voltage before diagnostic decisions are made.

Summary

Accurate measurements are the foundation of successful automotive diagnostics. While professional calibration equipment remains the ultimate method of verification, practical workshop checks can be performed using readily available batteryvoltage references. Understanding batterydischarge characteristics allows technicians

to select the most suitable reference source for the task. For checking oscilloscope voltage accuracy: • Regulated lithium batteries provide the most stable reference • NiMH batteries provide a useful alternative • Carbon-zinc batteries are generally less suitable because their voltage changes significantly during discharge A disciplined measurement approach helps ensure the waveform displayed on the oscilloscope represents the true condition of the vehicle system being tested. Please note: The battery-discharge graphs shown in this article are intended as general approximations only. Actual discharge characteristics vary between manufacturers and battery designs. Readers should consult the referenced publications for detailed technical data (see references).

Until next issue

Having confirmed the accuracy of the voltage scale (Y axis), what device would you use to check the oscilloscope time base (X axis)? Hint: An extension lead! By touching the oscilloscope probe tip with a finger, the human body can act as an antenna and pick up electrical interference from the surrounding environment. This simple exercise can be used to demonstrate the relationship between the time base, trigger controls and vertical scaling. More on that in the next issue.

Acknowledgements

The authors would like to sincerely thank Jamie Andrews and Fuzail (Phil) Shaik for their practical insight, technical observations and ongoing support.

References

1. Linden, D. & Reddy T.B. (Editors). Handbook of Batteries, 3rd Edition. McGraw-Hill, New York, 2002. 2. Reddy T.B. (Editor). Linden’s Handbook of Batteries, 4th Edition. McGraw-Hill, New York, 2011.

4 The Automotive Technician 29

Value diagnostics Gil Sher

When a rich code isn’t fuel: The Subaru Forester that needed a ground-up fix

2014 Subaru Forester arrived at our workshop with a story most technicians know too well, a persistent P0172 – System too rich code that had survived more than a year of parts swapping, repeated dealer visits and growing customer frustration. What followed was a textbook example of why modern diagnostics must go beyond components and into the electrical foundations that make them work.

A long trail of repairs – and no resolution

The customer had first spent eight months with her regular mechanic, who had cleaned the intake, cleaned and then replaced the mass air flow (MAF) sensor and repeatedly cleared the codes. Nothing had changed. Next came the Subaru dealer. Over roughly eight visits over a year, the dealer had replaced the spark plugs, fuel filter, air filter and an oxygen (O2) sensor. Each time the vehicle was returned with the reassurance that ‘nothing was wrong’ yet the Forester had continued to idle poorly, illuminate the malfunction indicator light (MIL), disable the traction control and cruise control and repeatedly log P0172. By the time the customer reached us, she said she had felt resigned to living with the fault.

Initial assessment: The data didn’t lie

We began with a structured interview and a full scan. Both OBDII and Subaru enhanced data showed the same thing: • Short-term fuel trim (STFT) and long-term fuel trim (LTFT) around -29 per cent • Rich readings from both the front air/fuel (A/F) sensor and rear O2 sensor • Freeze-frame at idle: - Coolant 70°C - MAF 2.9 grams per second (g/s) - Intake air temperature (IAT) 48°C - Manifold absolute pressure (MAP) 34 kilopascals (kPa) The fuel pressure was correct, an injector leak-down test was performed, there was no external leak and removing the air filter didn’t change the MAF reading. Mechanically, nothing pointed to a rich condition. But one number stood out – the MAF at 2.9g/s. A healthy 2.5L Subaru should idle at 2.3-2.5g/s. A comparison with a known-good Forester confirmed it – 2.4g/s. The freeze frame told the story – the IAT was also out but not as noticeable. Trying 30 The Automotive Technician

to recreate the freeze-frame condition was not easy. During most operating conditions, it was hard to see the incorrect reporting as MAF at idle was mostly at 2.4-2.6. The powertrain control module (PCM) was being told the engine was inhaling more air than it actually was – and was adding fuel accordingly.

A simple experiment proved the theory

To confirm the PCM’s behaviour, we temporarily altered the MAF’s position in the housing, reducing the airflow through the sensing port. Instantly, the fuel trims returned close to zero. A volumetric efficiency test in this configuration showed the engine itself was healthy. The problem wasn’t fuel. It wasn’t air. It wasn’t mechanical. It was the signal.

The turning point: Loaded ground testing

Before diving into intake disassembly or signal-altering ‘fixes’, we consulted ‘The Professor’, Scott Thomas from TaT, who recommended a loaded ground test. This proved decisive. Testing the grounds for the MAF, IAT, MAP, PCM, and the main engine/chassis grounds revealed a voltage drop under load – a lifted ground affecting both the MAF and the IAT. A temporary jumper wire from the MAF ground to the battery negative immediately normalised fuel trims. After two test drives, the P0172 code moved to history. The root cause had finally surfaced.

The real fix: Restoring ground integrity The shared grounds for the IAT and MAF sit beneath the throttle body on the intake manifold near the bellhousing – an area prone to corrosion and poor contact. The repair involved: • Removing the ground lugs • Re-crimping the terminals • Cleaning all contact surfaces • Reassembling and retesting

Post-repair data told the story: • MAF at idle: 2.4g/s • IAT and MAP readings more realistic • Fuel trims normal • No MIL, no driveability issues The Forester was finally fixed – without replacing a single additional part.

Lessons from the case

This Forester highlights several truths every modern technician should keep in mind: • Electrical integrity is foundational. A lifted ground can mimic multiple sensor failures. • Loaded testing beats continuity checks. Only voltage drop under load reveals the real story. • Known-good data is invaluable. A simple comparison MAF reading cracked the case. The ‘Good Scan & Scope Data’ section on the TaT website has tens of thousands of known-good module captures to compare your readings against. • Parts replacement is not diagnosis. Many components were replaced unnecessarily before the root cause was found. •

Collaboration matters. A quick consult with TaT helped steer the diagnostic process in the right direction.

Conclusion

After 18 months, multiple workshops and a trail of replaced parts, the solution to this stubborn P0172 came down to something deceptively simple – a bad ground.

In an era where vehicles rely on precise sensor data, even a small voltage drop can send an engine management system down the wrong path. This case is a reminder that sometimes the most powerful diagnostic tool isn’t a scan tool – it’s a methodical approach and a willingness to test the basics properly.

Simplifying sealant selection for today’s workshop

odern workshops are under constant pressure to complete repairs faster without compromising quality and choosing the right sealing solution is just as important as the repair itself, helping reduce downtime and keep vehicles moving. Building on its trusted range of traditional gaskets and sealing products, Permaseal has introduced a new range of RTV Silicone Sealants engineered for today’s workshop. Covering more than 12 million vehicles on the road, the range complements existing gasket offerings, helping reduce time spent sourcing parts and improving turnaround times. Featuring three application-specific products – Sump, Housing, and Manifold & Exhaust – the range is designed around how people actually work. Rather than relying on complicated colour-coded labels, each product is clearly named after its primary application, helping technicians quickly identify the correct product. The bold, workshop-ready packaging also makes each product easy to identify.

Sump

A neutral-cure, high-performance flexible RTV sealant suitable for engine and driveline applications with permanent oil contact or

oil wash such as sumps and timing covers. Its flexibility also makes it suitable for sealing differing materials such as pressed metal to solid blocks. The oximecure, sensor-safe silicone can withstand operating temperatures to 260°C with intermittent spikes to 371°C.

Manifold & Exhaust

A neutral-cure, high-temperature RTV sealant suitable for engine applications subject to higher temperatures and wider sealing surfaces. The oxime-cure, sensorsafe silicone can withstand operating temperatures to 399°C.

Housing

A neutral-cure, high-performance RTV sealant suitable for engine applications subject to high vibration or high torque loads due to close bolt spacing on cast housings that require less flexibility. The oxime-cure,

sensor-safe silicone can withstand operating temperatures to 260°C, with intermittent spikes to 371°C. Designed for professional workshops, the Permaseal RTV Silicone Sealant range provides application-specific options intended to simplify product selection. All three sealant varieties are available in 85g tubes for larger jobs and multiple applications. For added convenience, Sump and Housing are also available in single-use 15g tubes, with Manifold & Exhaust 15g coming soon. • Find out more, including technical specifications, application information and safety data, at permaseal.co or permaseal.co.nz

The Automotive Technician 33

Expanded EV rebates back independent workshops T he Australian Automotive Aftermarket Association (AAAA) has welcomed the Australian Government’s expansion of the DRIVEN program to help eligible independent repairers invest in equipment needed to safely service and repair electric vehicles (EVs).

Round three of the Dealership and Repairer Initiative for Vehicle Electrification Nationally (DRIVEN) Charger Rebate Stream is now open and will close on April 30, 2027. Eligible dealerships and EV repairers can claim up to 80 per cent of eligible expenditure on EV-specific workshop equipment, tools, personal protective equipment (PPE) and lifting equipment. Rebates of up to $3000 are also available for each eligible fixed smart charging plug or portable DC charger. The total rebate is capped at $50,000 per eligible site, including up to $21,000 for charging infrastructure. Independent repair businesses do not need to be affiliated with a vehicle dealer or manufacturer to qualify. Eligible purchases include high-voltage PPE and insulated tools, lockout and warning equipment, electrical testing and battery diagnostic equipment, EV-specific scan tools, battery storage and containment equipment, battery lifting tables and EVspecific hoists or access equipment.

34 The Automotive Technician

AAAA Chief Executive Officer Stuart Charity said the change recognised the significant investment being made by independent repairers. ‘Independent workshops are preparing to service and repair a growing number of EVs,’ said Charity. ‘This requires investment in technician training, high-voltage (HV) safety, diagnostic and scan tools, batteryhandling equipment and specialised lifting capability, ensuring motorists can continue to choose where their vehicles are serviced and repaired.’ Full eligibility requirements, guidelines and applications are available on the Australian Government’s DRIVEN Charger Rebate

Stream webpage. Applications are assessed in order of receipt and may close early if funding is exhausted.

Charity encouraged eligible repairers to review the guidelines, identify the equipment they needed and apply early. ‘This is a significant opportunity for independent workshops investing in EV capability and we encourage eligible repairers to consider bringing forward planned investments and apply as early as possible,’ said Charity. •

Find out more about the DRIVEN Charger Rebate Stream at business.gov.au/grantsand-programs/driven-charger-rebate-stream

New boosters for two Aussie icons

or many workshops, sourcing quality replacement components for ageing Australian vehicles is an increasingly challenging task.

Although the Holden Commodore and Ford Falcon are no longer in production, thousands remain on Australian roads, sustaining ongoing demand for reliable service and repair solutions. Protex is helping meet that demand by introducing two new brake boosters designed specifically for these iconic vehicles.

The new Protex boosters use the original plastic-bodied OE design, providing a direct replacement for factory-installed units in Holden Commodore VS models (1995-2000) and Ford Falcon EF-AU models (1994-2000). Designed to replicate the original fit, form and function, they enable workshops to complete repairs with confidence while preserving vehicle performance and pedal feel. What sets these boosters apart is their focus on supporting hardto-source applications. Both units have been re-tooled specifically for ageing vehicles, where OE replacement options are no longer available. During development, the boosters were tested to relevant SAE International standards to ensure reliable performance and durability.

As part of the Protex range, these new boosters are backed by more than 25 years of braking experience, OE-grade fit and reliability, broad vehicle coverage and nationwide support. This gives resellers and workshops confidence that they are supplying quality braking solutions from a trusted Australian aftermarket brand. For businesses servicing Australia’s vehicle parc, these new

additions offer an opportunity to support owners of two of the country’s most recognised vehicles and to address growing demand for quality replacement parts.

Why Protex?

For more than 25 years, Protex has been trusted by the Australian aftermarket to deliver reliable braking solutions, supported by comprehensive vehicle coverage and consistent quality. Whether servicing everyday passenger vehicles, hard-working commercial fleets or growing 4WD applications, Protex continues to invest in expanding its range to help resellers meet market demand with confidence. Explore the expanded Protex Booster range today to discover more opportunities to support your customers with a complete braking solution. • Find out more about the Protex range at protexparts.com.au

The Automotive Technician 39

Troubleshooting Hyundai iLoad D4CB turbocharger failure and replacement T he Hyundai D4CB 2.5-litre CRDi engine used in iLoad and iMax vans, particularly 2008-14 models, has developed a reputation for turbocharger failure.

However, the OEM turbocharger is rarely the underlying problem. In many cases, failure results from inadequate maintenance, oil contamination or restricted lubrication. Worn injector seals, blocked oil pick-up strainers and sludge accumulation can progressively affect lubrication and combustion quality until turbocharger or even engine failure occurs.

Importantly, always identify and rectify the cause of the original turbo failure before fitting a replacement. Otherwise, the new turbocharger may suffer exactly the same fate.

The main causes of failure include oil starvation from a blocked oil pick-up, soot accumulation around the variable-nozzle turbine (VNT) mechanism and foreign-object damage.

Affected vehicles commonly use the BorgWarner BV43-2074 turbocharger (part number BW53039980145). When replacing the turbocharger, remove the sump and thoroughly clean out sludge and the oil pick-up strainer. Inspect the cam-chain guides as their Teflon material can delaminate and contribute to oil system blockages. Remove and clean the intercooler and inspect all intercooler hoses for cracks or deterioration. The oil filter should also be cut open and inspected for bearing material, which may indicate developing engine damage. Check oil flow through the oil heat exchanger as restrictions can reduce lubrication to the turbocharger. The injectors should also be removed and their seals inspected. Worn seals can allow compression and combustion contamination into the cylinder head, contributing to sludge formation and soot deposits around the VNT mechanism. This can eventually cause the vanes to stick or seize. Replace the air cleaner with a genuine new unit, refill the engine with oil meeting Hyundai specifications and always replace the turbocharger oil-feed pipe. Once assembled, smoke-test the intake system for pressure leaks. Boost leaks can cause the turbocharger to operate outside its intended range and potentially overspeed.

The catalytic converter and exhaust system should also be checked for restrictions that may create excessive back-pressure. Finally, carry out a full scan-tool diagnosis. Confirm relevant sensors and enginemanagement systems are operating correctly, rectify faults, clear diagnostic trouble codes and retest.

Turbo myth busting

Turbochargers are generally extremely reliable when correctly lubricated and maintained. Manufacturing defects account for only a small proportion of failures, while the overwhelming majority are associated with oil starvation, contaminated oil or foreignobject damage. The most important rule remains simple – never replace a failed turbocharger without determining why the original unit failed. GCG Turbos supplies new and refurbished OE-quality replacement turbochargers. • Find out more at gcg.com.au or call 1300 TURBOS

i-Stop warning due to transmission fault A flashing i-Stop light and inoperative stop/start system on this 2013 Mazda 6 with 80,098km on the odometer turned out to be the result of a transmissionrelated electrical fault rather than an i-Stop problem itself. A diagnostic scan revealed P181F:00-2E – Electric transmission fluid pump control module command signal circuit and other stored faults, and all codes returned after clearing.

Testing then focused on the electric transmissionfluid pump circuit. The pump had battery supply through a relay, a direct ground, an ignition 12V supply and a communication/control wire but the control wire showed no activity and the relay was not being commanded on. Used OEM Mazda wiring information to trace the circuit further, which confirmed the transmission control module (TCM) is integrated into the transmission assembly. The key find was a connector fault between the relay and the TCM.

A female terminal was not making proper contact 40 The Automotive Technician

with the matching male pin, which prevented the relay from being controlled and stopped the electric transmission-fluid pump from operating. That in turn inhibited the i-Stop system. Repairing the connector and restoring proper pin contact between the relay and the TCM brought the pump back into operation. After clearing the fault codes and confirming they did not return, the i-Stop system also resumed normal operation. Diagnostic time for this job was approximately three hours of preparation and research, plus 15 minutes problem-solving on the car. Repair time was 45 minutes. Erwin Bruce, T.A.R Diagnostic Inc BARBADOS

Understanding brake shudder and the role of brake-disc design B rake shudder is a common braking issue, typically felt as a brakepedal pulsation or a booming noise.

Determining whether the condition is thermal or cold shudder is an important first step in identifying the underlying cause and selecting the appropriate repair.

Thermal shudder

Thermal shudder generally occurs during deceleration from high speeds and produces a booming noise, typically in the 100-250 Hertz (Hz) range. The effects of hot shudder can usually be identified by a circular pattern of spots on the friction surfaces of the brake disc. Inspection may reveal circular spots on the brake disc’s friction surface caused by resin deposits from the brake pad.

Cold shudder

Rotor runout creates steering-wheel vibration, which occurs during normal braking which then creates disc thickness variation (DTV). This can be identified by pulsation in the brake pedal, torque fluctuations in the steering wheel and/or vibration of axle and chassis components.

It operates at a much lower frequency than thermal shudder, approximately 5-50Hz and can occur during normal braking regardless of temperature.

The primary cause of DTV is rotor runout with wheel imbalance, bearing defects and other suspension or steering issues potentially amplifying the symptoms.

Inspection is key

Because brake shudder can result from several factors, technicians should inspect the entire braking and surrounding systems.

Misuse of a pneumatic rattle gun can cause uneven or excessive tightening, which can distort the brake disc and hub assembly. Best to use a torque wrench for correct and even tension. Hub-mounting faces must be thoroughly cleaned before fitting new rotors. Corrosion, dirt or scoring on the mounting surface can prevent the rotor from seating flush, causing runout and brake shudder. Clean the carrier and guide pins to prevent shuddering and noise. Lubricate the contact points with high-temperature grease (see image on this page).

TRW Slotted Brake Disc now available TRW’s Slotted Brake Disc has recently been introduced to the local ZF Aftermarket braking portfolio. It features a patented slot design engineered to disperse water, dust, debris and gases from the friction surface while continuously renewing the contact surface. Manufactured from high-carbon GG15HC, the discs are designed to provide effective heat dissipation and stability under heavy braking, helping minimise distortion and cracking.

For workshops, understanding the causes of shuddering and selecting a brake disc engineered to manage heat, contamination and friction effectively can help deliver smoother, more consistent braking performance. •

To find out more about the TRW braking range contact ZF Services Australia on 02 9679 5555, email customersolutions.au@zf.com or go to zf.com/au

The Automotive Technician 43

TaT Biz Geoff Mutton

Business Resources

Are you ready for the repairs customers have been putting off?

or the past couple of years I’ve been talking about customers extending service intervals and putting off non-essential repairs because of cost-of-living pressures. The problem with delaying vehicle maintenance is the work doesn’t simply disappear. Eventually it catches up. With Christmas approaching, I believe many workshops could see exactly that happen over the next couple of months. Customers who have stretched out their servicing or put off recommended repairs will start thinking about holidays, long trips and whether their vehicle is going to get them there and back reliably. This could create a welcome increase in work but don’t expect it all to be straightforward servicing. Vehicles that haven’t been properly maintained can bring bigger repairs, more diagnostic work and more difficult conversations with customers who may still be watching every dollar. Here are seven things to consider as we head towards the Christmas rush.

1. Expect the job mix to change

Ten cars booked in for routine servicing is very different to 10 cars arriving with overdue servicing, warning lights, noises and a list of repairs that have been put off for six months. Be prepared for jobs to grow once vehicles are inspected. Something that may have been a relatively simple repair six months ago could now be more involved and expensive. Allow some flexibility in your booking diary rather than filling every available hour. Being busy is great but being so busy that standards start to slip isn’t.

with sales messages. Target customers where there is a genuine reason to make contact. If you recommended work six months ago and the customer is likely to be travelling over Christmas, a friendly reminder could be appreciated. It might be as simple as saying, ‘We recommended this repair at your last service. If you’re planning on travelling over Christmas, now would be a good time to get it sorted.’ You’re helping the customer while bringing legitimate work back into the workshop.

4. Don’t overbook

When the Christmas rush arrives, the temptation is to squeeze everyone in. Be careful. If vehicles have been neglected, the amount of work you find could be considerably more than expected. Overbooking puts pressure on technicians, increases mistakes and leads to rushed inspections. You can also end up disappointing customers when promised completion times aren’t met. Know what your workshop can comfortably handle and stick to it. There’s little point increasing sales if the extra work results in overtime, comebacks and unhappy customers.

5. Inspect every vehicle properly

Get into the habit of reviewing the customer’s vehicle history before it arrives. What did you recommend at the last service? Were the brakes getting low? Was there a coolant leak? Were the engine mounts starting to fail? Was a timing belt due? Did the customer decline something because money was tight? Knowing this before the vehicle arrives allows you to have the conversation with the customer at drop-off rather than discovering it halfway through the day. It also gives you a much better idea of what that booking could turn into.

When workshops get busy, it’s easy for service standards to slip. Regularly remind your technicians that every vehicle deserves a thorough inspection and a properly completed service report. Any maintenance items, safety concerns or recommended repairs should be clearly documented and communicated to the customer. This is particularly important when customers have been stretching service intervals. This isn’t about overselling or inventing work that doesn’t need doing. It’s about making sure customers are fully informed about the condition of their vehicle. Consistency is the key. When every vehicle is inspected to the same high standard, fewer legitimate repair opportunities are missed and the customer gets a better outcome.

October is a good time to start reviewing previously recommended work that customers have put off. This isn’t about bombarding your database

This could be one of the most important skills for workshops over the next few months. You may inspect a vehicle and find $3000 worth of work but the customer simply doesn’t have $3000 available.

2. Review the vehicle history before it arrives

3. Contact customers with outstanding repairs

44 The Automotive Technician

6. Help customers prioritise repairs

Don’t immediately write them off as a customer. Help them prioritise. What needs to be done immediately for safety or reliability? What should ideally be completed before a long Christmas trip? What can reasonably wait until January or the next service? Breaking a large repair bill into manageable stages can help the customer get their vehicle back up to standard without putting unnecessary pressure on their household budget. It also builds trust because you’re helping them make an informed decision rather than simply presenting them with a large bill.

7. Protect yourself on larger repairs

Delayed maintenance can quickly turn into expensive repair work. If you’re ordering thousands of dollars’ worth of parts, make sure the customer has clearly approved the job and consider taking a deposit before ordering expensive or non-returnable components. Don’t become the customer’s bank. We’ve all heard stories of workshops completing major repairs only to have the customer say, ‘I can’t pay for it until next week.’ Good communication before starting the repair protects both parties and avoids an uncomfortable conversation when the vehicle is ready for collection.

Make the most of the opportunity

The lead-up to Christmas could be a busy period for many workshops, particularly as customers finally address maintenance and repairs they’ve been putting off. That’s a good opportunity for our industry but it needs to be managed properly. Don’t simply try to cram more vehicles through the door. Review vehicle histories, communicate with customers, inspect every vehicle properly and help customers prioritise what genuinely needs doing. Customers have had a tough couple of years and many are still watching every dollar. If we can help them get their vehicles safe and reliable for Christmas while charging fairly for the work we perform, everyone wins. The work customers have been putting off hasn’t disappeared. Eventually it catches up.