$16.50 inc. GST
September 2026
GWM’s BIG GUN In the trench with a Cannon Alpha PHEV
Testing a Li-ion battery in an EV or PHEV
HiAce 2TR-FE
Coolant replacement feature
INDEX 6003
GWM Cannon Alpha PHEV: A technician’s overview
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Li-ion Batteries: What you need to know
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Toyota HiAce 2TR-FE: Coolant replacement procedure
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How to test a Li-ion battery in an EV or PHEV
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SEP 2026
GWM Cannon Alpha PHEV We check out this son-of-a-gun
DIAGRAM 1
2025-Onward GWM Cannon Alpha PHEV 2.0L GW4N20A The Australian 4WD ute market is undergoing a massive structural shift. While 4x4 utes still account for roughly one in every five new vehicles sold in Australia, the quick arrival of alternative powertrain options has fundamentally shifted buyer expectations and forced legacy manufacturers to adapt. One of these new arrivals is the GWM Cannon Alpha PHEV, a high-value alternative to a traditional turbodiesel ute with some limitations you might be able to live with. DIAGRAM 2
In late 2022, GWM designed a significantly larger, more luxurious ute variant, based on the heavyduty Tank 500 SUV chassis, to replace the Steed and UTE models. In China, it was called the Shanhai Cannon but was rebranded as the Cannon Alpha in 2023 for Western markets. For more information on the previous models, see the following article. GWM Ute Cannon Features and Specifications Tech Talk, July 2024, page 5589
Beer O’Clock Hill
The global commercial market saw a massive influx of new-energy vehicles (NEVs) being planned, notably the BYD Shark 6 and the Ford Ranger PHEV. This led GWM to develop the Plug-in Hybrid Electric Vehicle (PHEV) driveline—specifically their Hi4-T (Hybrid Intelligent 4WD for Off-Road) architecture, which was fitted into their advanced intelligent off-road platform (shared with the Tank 500 SUV). See Diagram 2 This resulted in the GWM Poer Sahar, which was marketed in Australia
Hi4-T drive line layout
2.0L Turbo Petrol Engine
9-Speed transmission
Electric drive motor
SEP 2026
Transfer case
Traction battery A
Traction battery B
Fuel tank
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DIAGRAM 3
Front underside service points
Engine oil filter
Front differential filler plug Front differential drain plug
Engine sump plug
High-pressure transmission filter
Transmission drain, level and refill point. You will need to remove this plug then rotate the mechanism to the point you want.
Transmission ID plate
Fuel filter
Transfer case filler plug
Transfer case drain plug
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SEP 2026
DIAGRAM 4
Battery pack heat exchanger module The battery pack heat exchanger module is mounted under the vehicle, and the AC lines appear to be exposed to damage if you plan on doing a lot of off-roading
and New Zealand in mid-2024 as the GWM Cannon Alpha. The PHEV variant was released in 2025. The reason we have given you this history lesson on the names is that the Poer capital “P” is used in the logo and in the design of the key fob, and it is the name you might have to look up in your diagnostic tool and select for the tool to communicate with the vehicle.
The driveline The Cannon Alpha PHEV shares many similarities with its turbodiesel sibling. Rather than deleting the mechanical drivetrain and replacing it with separate electric axle motors, GWM used a P2 architecture. They sandwiched a powerful 120kW electric motor directly between the 2.0-litre turbo petrol engine and the transmission. This approach allows the combined output of the engine and electric motor to flow through the 9-speed DIAGRAM 5
gearbox, and the vehicle preserves its physical driveshafts, lowrange transfer case, and locking differentials. See Diagram 3 One difference is the rear suspension, the leaf springs on the diesel models have been replaced with a multi-link coil-spring live axle setup. This manages the extra weight of the batteries while significantly improving unladen ride comfort. See Diagram 11 This PHEV uses a 2.0L turbocharged direct-injected petrol engine with hydraulic tappets and a timing chain. It is capable of operating on the Miller cycle which improves fuel efficiency by keeping the intake valve open longer during the compression stroke or closing it earlier, paired with forced induction or hybrid assistance, delivering up to 10%-15% better fuel economy than a standard Otto-cycle engine. It has an identification code of GW4N20A.
Rear service points
Traction battery B
SEP 2026
Explosion-proof valves
The 9-speed transmission (HYT9HAT2-01) is manufactured by HYCET Transmission Technology, a wholly owned subsidiary of Great Wall Motor (GWM). Through a partnership with BorgWarner, this unit uses BorgWarner’s onaxis P2 drive module, which combines an electric motor and a triple-clutch system, allowing the system to decouple from the engine for pure electric driving or to assist when required. These components combine to form the Hi4-T system, which gives the Cannon Alpha PHEV excellent offroad capabilities. It is the first PHEV to climb Queensland’s legendary Beer O’Clock Hill, and it did so very close to factory standard - the only modification was a set of Mickey Thompson A/T tyres. See Diagram 1 Vehicle-to-Load (V2L) capabilities are becoming an expectation for modern utes, and this vehicle can deliver up to 3.3kW of output, enabling the Cannon Alpha to power devices and appliances providing an “off-the-grid” option, perfect for camping or the work site.
The luxury features Utes are no longer just utilitarian workhorses built solely for muddy boots and job sites, as this vehicle seamlessly blends dual-cab capability with the refined DNA of a premium continental limousine. The front row seats are six-way poweradjustable, heated, ventilated, and equipped with a massage function. The rear seats are also power-adjustable, heated, and Rear differential filler plug
Rear differential drain plug
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Service specifications for the GWM Cannon Alpha PHEV
DIAGRAM 6
Fluid specifications
GWM GW4N20A
Wheel alignment
Engine Oil Specification
SP / C5 0W-20
Front Toe Individual
5’ ± 5’
Engine Oil Capacity
5.9L with filter
Coolant Specification
Ethylene glycol
Camber
12’ ± 30’
High Temp Coolant Capacity
9.35L ±0.3L
Caster
3.7° ± 30’
Low Temp Coolant Capacity
9.33L ± 0.3L
KPI
12°3’ ± 30’
Transmission Oil Specification
GWM ATF 9
Rear Toe Individual
0’ ± 30’
Transmission Oil Capacity
11.2L ± 0.1L
Thrust angle
0° ± 15’
Transfer case Oil Specification
MERCON LV
Toe Lock Nut
63 ± 5 Nm
Transfer case Oil Capacity
1.5L
Lower Control Arm Bolts / Nuts
240 Nm
Front Final Drive Oil Specification
DUAL 9 FE 75W-90
Front Driveshaft Nuts
370 ± 30 Nm
Front Final Drive Oil Capacity
1.5L
Wheel Nuts
120 ± 10 Nm
Rear Final Drive Oil Specification
DUAL 9 FE 75W-90
Rear Final Drive Oil Capacity
3.2L ± 0.1L
Torque specification
Refrigerant Type
HFC-134a
Engine Sump Plug
25 Nm
Refrigerant Capacity (Single Evap)
600 ± 10g
Refrigerant Capacity (Dual Evap)
1150 ± 15g
Engine Oil Filter
25-30 Nm
A/C Oil Type
ND-OIL11
Spark Plugs
22 Nm
A/C Oil Capacity
220 - 235 ml
Front Final Drive Filler Plug
33 Nm
Brake Fluid
DOT 4
Front Final Drive Drain Plug
33 Nm
Rear Final Drive Filler Plug
150 Nm*
Rear Final Drive Drain Plug
150 Nm*
Brake specification Front Brake Rotor Min. Thickness
31 mm
Transfer case Filler Plug
38-48 Nm
Rear Brake Rotor Min. Thickness
20 mm
Transfer case Drain Plug
38-48 Nm
Front Caliper Bolt
280 Nm
Rear Caliper Bolt
180 Nm
DIAGRAM 7
*OE specification. Confirm against current service information before application.
60/40 split tailgate and spare wheel location
The tailgate is electrically opened via a button in the middle of the “P” shaped logo on the rear of the tailgate. One push opens the tailgate, and it all folds down. A quick double push will open the 60/40 split like a barn door. The one we tested had reliability issues, possibly caused by some previous abuse.
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SEP 2026
DIAGRAM 8
Under bonnet locations
Brake fluid
AC service points
Low-temperature cooling system reservoir
Motor control unit
Hightemperature cooling system reservoir
Washer fluid
High-voltage disconnect
cooled. To make up for the lack of a massage function, the rear passengers can look out of the panoramic glass sunroof. GWM’s premium philosophy extends to the vehicle’s exterior functionality. The standout feature is the innovative 60/40 split tailgate, which can open like barn doors for quick access or lower traditionally to handle heavy loads. An electronically powered rear sliding window is offered, but I am not sure what the advantage is. See Diagram 7
What is the view like underneath? Once on the hoist and the front bash plate removed, there is nothing overly complicated to see. Service points are easy to find and access. The transmission uses a plastic pan, which is not uncommon. However, it uses a drain-and-refill system similar to a Mercedes-Benz transmission, SEP 2026
Engine number
which requires a tool to turn the plug to different positions for draining, refilling, and level checking. There will be a future article on this procedure. The transmission also has an external electric oil pump and filter on the RH side. See Diagram 3 The fuel filter is mounted to the chassis rail and is easy to access. However, in the vehicle we inspected, the fuel filter and most of the rear of the transfer case were covered with a significant amount of black, tar-like overspray, which could make component removal difficult. See Diagram 3 Between the fuel tank and transfer case is the battery pack heat exchanger module. This uses air conditioning refrigerant and a heat exchanger unit to cool the liquid coolant for the HV system component and the batteries. This has no bash plate protection, and in my opinion, the AC line looks vulnerable to snagging on sticks
12 volt battery jump start point on the positive terminal
if you intend to use this vehicle for a lot of off-roading. I would be making a bash plate for this unit if I bought one. See Diagram 4
Under the bonnet Again, all of the service points are easy to find, or you might need to remove the plastic covers over the front of the engine, which are held in place with clips that you DIAGRAM 9
Centre console locations Transmission park release.
Place the key fob here to start the car if the fob battery is flat.
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need to press in the middle to release. The engine has one belt that drives the coolant pump, and the engine number is on the timing cover at the right-hand front of the engine. Apart from the orange high-voltage cables going to the drive motor controller, it is a normal petrol engine. See Diagram 8
DIAGRAM 10 VIN location
What is it like to drive? We didn’t have a chance to take it off-road, but by the amount of mud caked under the car and the bumps and scratches it has, the previous set of journalists did give it a workout. On the highway and around town, it was very smooth and comfortable if driven conservatively. As with most other modern electricdrive vehicles, there is an option to select sports mode, which in most cases gives the vehicle some more get-up-and-go. DIAGRAM 11
The VIN is stamped into the chassis rail, visible through the right-hand front wheel arch.
However, with the Cannon Alpha PHEV, this is not such a big performance gain, and it makes the petrol engine rev hard, and the transmission seems to get confused as to which gear it needs to be in. I would not be surprised if a software update smooths this out in the near
Front and rear suspension view
future. It certainly does not have the sheer acceleration of the BYD Shark 6, which is more of an EV with an add-on petrol engine, whereas the Cannon Alpha is more of a petrol vehicle with some EV added on to preserve its off-road capabilities. One small niggle was the button for the 60/40 split tailgate. The button in the middle of the logo of the tailgate has a rubber cover that seemed loose and was getting out of position, which caused some difficulty using the tailgate. See Diagram 7
Conclusion
With coil springs on the front and rear suspension and cam bolts for wheel alignment adjustments, there is nothing overly complicated and it all looks robust.
The sales of GWM Cannon Alpha PHEV demonstrates how quickly Australia’s ute market is changing. In 2025, 1,371 were sold, which is helping establish electrified dualcab utes as a credible market segment. This vehicle and other like it has increased pressure on established manufacturers to deliver better value and practical electrified drivetrains without sacrificing off-road performance. Our impression is that it seems like an easy vehicle to service, with only a few details we would change. But as always, we will have to wait and see how these new brands stack up over time. For more information on a wide range of vehicles, log onto VACC MotorTech or call VACC’s TechAdvisory service.
Thank you to Chris and the team at Smarter Choice Auto in North Melbourne for their assistance with this article.
smarterchoiceauto.com.au 03 9828 4237 6008
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Periodic table
DIAGRAM 1
Lithium is a metal element that is used in combination with other elements and chemicals to create a family of different battery cells that are commonly used in EVs and PHEVs. The cells shown here are cylindrical, but other formats exist.
High-voltage batteries seem to be a mystery to many motorists and possibly to many technicians. Lithium-ion batteries have received a lot of media attention and are a hot topic. However, there are many different types of lithium battery, with varying properties, and the number of vehicles using them keeps growing. Now is the time to understand these batteries properly - and bust a few myths. Lithium is a soft, silvery-white metal and has atomic number 3 on the periodic table of elements. Most batteries do not use lithium in its metallic form as the main DIAGRAM 2
Lithium-ion batteries.. what you need to know storage material. They use lithium-ion chemistry, in which lithium ions move between the positive and negative electrodes during charge and discharge.
Common Li-ion battery chemistries LFP and NMC/NCA
These images show prismatic battery cells with two different chemistries. The data in the table below shows the voltage ranges. NMC and NCA are very similar, but LFP has a different range and discharge curve, as shown in the diagram 3.
Li-ion Cell chemistry
Low SOC
Nominal voltage
High SOC
LFP / LiFePO4 Lithium iron phosphate
~2.8–3.1 V
3.2–3.3 V
~3.4–3.6 V
NMC / NCM* Nickel manganese cobalt
~3.0–3.4 V
3.6–3.7 V
~3.9–4.2 V
NCA* Nickel cobalt aluminium
~3.0–3.4 V
3.6–3.7 V
~3.9–4.15 V
*Some diagnostic tools might ask you to identify the battery and will give you the option of “ternary lithium battery”. This means it could be NMC / NCM or NCA as they are a mixture of three different elements, but not LFP.
SEP 2026
Only 3-6% of the battery is lithium depending on the design. Lithium is used in batteries because it gives a very useful combination of energy density, power capability, rechargeability, weight, packaging flexibility and long service life. The trade-off is that lithium-ion based batteries are chemically active and temperature-sensitive, and require complex systems for them to remain reliable and safe. Lithium-ion (Li-ion) is not just one type of battery; it is a family of chemistries. The major differences are usually in the cathode, or positive electrode material. There are many variants with different metal ratios which are used in a wide array of applications. We will only cover the more common ones used in passenger EVs and PHEV which are NMC, NCA, and LFP.
Lithium Nickel Cobalt Aluminium Oxide (NCA) NCA batteries are used where high energy density is a priority, such as long-range and high-performance vehicles, but they need tighter thermal and voltage management to maintain performance and durability. This type of battery is used in many Tesla vehicles. 6009
DIAGRAM 3
Voltage curve of LFP and NMC/NCA battery cells Having an understanding of how the different battery cells operate and their voltage characteristics will be helpful for future diagnostic procedures.
Lithium Nickel Manganese Cobalt Oxide (NMC or NCM) NMC is widely used because it gives a strong balance of energy density, power, lifespan and cost. The nickel content increases energy density, manganese improves structural stability, and cobalt helps stability and performance. NMC batteries are more common in European, Korean, Japanese and North American BEVs and PHEVs. There are multiple subvariants with different mixtures of these ingredients, depending on the application.
Lithium Iron Phosphate (LFP or LiFePO4) LFP is a newer chemistry that has become very important in EVs because it is comparatively lowcost, durable, thermally stable, and DIAGRAM 4
*Combined incident counts from Norway, New South Wales and South Korea.
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free of nickel and cobalt, which have various ethical problems. Its main drawback is lower cell-level energy density, although modern pack design has reduced this disadvantage. LFP accounted for over 55% of EV batteries deployed globally in 2025. These batteries are commonly found in Chinese EVs, some Chinese-made Teslas, and BYD vehicles. An LFP battery is less likely to catch fire from puncture damage, and if it does ignite, it tends to be less aggressive than an NMC or NCA battery.
Cell designs and voltage The above chemistries are used to make battery cells that can produce voltage. The three dominant EV cell formats are cylindrical, pouch, and prismatic, and they can use any
Reported EV and ICEV fires in three 2022 datasets* While the media implies a growing epidemic of battery failures, official records show the opposite. Many more internal combustion engine vehicles (ICEV) catch fire than EVs. Because ICE vehicles substantially outnumber EVs, this pie chart describes the distribution of reported incidents rather than the relative fire risk of individual vehicles.
chemistry. The new BYD Blade cell is a longer prismatic design that uses LFP chemistry. The difference in format or design can influence the capacity of the individual cell, but the chemistry determines the cell’s voltage output. See Diagram 1 & 2 An LFP cell commonly has a nominal voltage of 3.2V and shows 3.65V when fully charged. An NMC /NCA could have a nominal voltage of 3.6-3.7V and show 4.2V when fully charged. Published cell specifications commonly state that LFP and NMC/NCA-type lithium-ion cells have a discharge cut-off at around 2.5 V per cell. See Diagram 3 LFP batteries have a very flat voltage curve through much of their state of charge (SOC) range. That means a small voltage difference may represent a larger SOC difference than expected in the middle of the range. Just using cell voltage reading for diagnostic purposes could mean very different things depending on chemistry. See Diagram 3 So, the key takeaway is that cell design determines how that cell is packaged, and chemistry determines the cell voltage, which is what you really need to know. These cells are then joined together inside the battery pack to produce the high voltage required by the vehicle’s driveline. See Diagram 5
I heard that they catch fire! Media reports on electric vehicle (EV) fires are heavily sensationalised, SEP 2026
DIAGRAM 5
What is in the battery pack
Protective casing
Battery management system control units
Insulation Battery cells packaged into modules. Cylindrical cells shown. Coolant passages to remove heat from the cells
A modern EV or PHEV battery pack is a sophisticated combination of battery cells, cooling systems, temperature sensors, voltagemonitoring wiring, circuit-disconnection contacts, and computer control units that make up the battery management system – all sealed in a water and air-tight protective casing mounted in a robust area of the car for maximum protection. But it’s not indestructible.
frequently creating a false public perception that EVs are highly combustible safety hazards. A traditional petrol car fire is rarely considered newsworthy because it happens so frequently. However, because electric powertrains are relatively new, any EV incident receives prominent, front-page national coverage. Also, media
reports regularly confuse highend electric car battery packs with cheap, uncertified mobility devices like e-scooters and hoverboards, which do suffer from frequent battery fires.
by the University of Queensland (Bretter, Nature Energy 2025) found that almost half of Australians wrongly believe that EVs are more likely to catch fire than petrol or diesel vehicles, a claim that is false.
Because of this heavily skewed coverage, public fear has risen sharply despite historically low incident numbers. A landmark study
Automotive lithium-ion battery packs are highly engineered systems designed to withstand extreme conditions. They have sophisticated
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DIAGRAM 6
Li-ion cell polarity flip - what happens when one weak cell in a series pack is forced below zero volts
If an EV or PHEV Li-ion battery cell discharges to zero voltage, it could flip polarity. This situation allows destructive internal chemical reactions, potentially causing a short circuit within the cell and leading to bigger problems, such as a fire. This is a rare occurrence if there is no physical damage to the battery and the battery management system is operational. (*Solid Electrolyte Interphase)
Battery Management Systems (BMS) that continuously monitor each cell’s voltage, current, and temperature. It instantly cuts power or stops charging if it detects any anomaly. Most EV and PHEV batteries have heating and cooling systems that actively regulate the battery pack’s temperature, keeping it in a safe operating window. The battery pack is protected against impacts to prevent cell damage. Cheap e-bikes and scooters have none of this.
What happens when it all goes wrong? But there have been occasions when Li-ion batteries have caught fire in EVs, and in most of these cases, the fire has been triggered by severe external forces or environmental extremes rather than an inherent fault. There are instances of extremely high-speed crashes damaging the battery, or of road debris piercing the underbody shield and directly entering the pack, creating an instant internal short circuit. Flooding of the vehicle, particularly seawater, can damage the power supply to the BMS, which is outside
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the HV battery. Without a BMS to manage temperatures, the battery can overheat and fail. The rarest but most published issue is a manufacturing defect, which can slowly degrade the internal cell wall over months or years.
What is a cell polarity flip? The BMS monitors the voltage ranges of the different cell types. It compares the highest voltage cell with the lowest voltage cell and measures the difference. Some manuals call this measurement the delta, after the uppercase Greek letter – a triangle, representing a measurable gap between two values. If the voltage delta exceeds the acceptable range, the vehicle will trigger diagnostic codes, and the battery management system will limit output and charging speeds. In an extreme situation, the BMS will shut down the battery and diagnostic codes will be recorded. However, if there is a serious fault in the battery, such as physical damage to the case that affects the cells or an internally damaged cell, it may be beyond the BMS’s capacity to handle. If a cell discharges well beyond its normal voltage range and approaches zero volts, it can cause a cell polarity flip. If this happens, the copper in the cell dissolves into the electrolyte,
then reforms and grows into sharp metal structures called dendrites that can short out the cell. This concentrated current flow generates intense localised heat inside the sealed cell, which, depending on the design, could cause swelling that can impact the adjacent cells. See Diagram 6
My little runaway If the heat builds up enough, the damaged battery cell can vent gases which can ignite. This, in turn, sets the neighbouring cells on fire and so on until the whole pack is ablaze. This is a self-sustaining chemical chain reaction known as thermal runaway, and there is not much you can do about it. However, as stated earlier, thermal runaway events are very rare if the vehicle is in good condition and the BMS is operational. And just because a cell is at or near zero volts, there is no guarantee that it will result in a fire. Based on market trends, the number of EVs and PHEVs with Liion batteries on Australian roads is growing, and service and repair opportunities abound for those who are prepared. See the article in this issue on how to test a Li-ion battery with your diagnostic tool, page 6015. For more information on the HV Data set in VACC MotorTech, log on or call VACC’s TechAdvisory Service. SEP 2026
HiAce 2TR-FE Coolant replacement procedure 2005–2019 Toyota HiAce 2TR–FE 2.7L The fifth-generation HiAce offered the 2TR–FE 2.7-litre petrol engine as an option from 2005 to 2019, and it has a very good reputation for its simplicity and durability. However, VACC’s TechAdvisory Service received the occasional call about an airlock in the cooling system and whether there is a bleeding procedure, and there is. Bleeding the air out of an engine has become harder over the years as cooling systems have evolved into complex computercontrolled thermal management systems. In many cases, you will need a vacuum coolant refill tool DIAGRAM 1
Radiator drain
Accessible from under the vehicle
SEP 2026
and a compatible diagnostic tool to set the vehicle into bleeding mode to ensure that there are no airlocks. For more information on these systems, see the following article:
VW/Audi Group: Coolant System Bleeding Tips TechTalk Sept 2024, page 5632
Luckily the HiAce with the 2TR-FE engine is relatively straightforward to bleed once you know where to bleed the air from.
WARNING: Do not remove the radiator reservoir cap while the engine and radiator are still hot. Pressurised hot engine coolant and steam may be released, causing serious burns.
Drain coolant 1.
Remove the radiator reservoir cap, which can be accessed from under the bonnet. See Diagram 4
2.
Loosen the radiator drain cock plug and drain the engine coolant. See Diagram 1
3.
Loosen the cylinder block water drain cock plug on the right-hand side of the engine, then drain the engine coolant. See Diagram 2 DIAGRAM 2
Engine block drain
Located on right-hand side of the engine.
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DIAGRAM 3
Location of the coolant bleed point “2-way” union
Once you have accessed the engine by lifting the passenger seat, at the rear of the throttle body is a coolant hose with a metal pipe or union, which Toyota call a “2-way”. Disconnect one of the hoses from this union until coolant begins to flow, then reconnect the hose.
Refill coolant 1.
Tighten the radiator drain cock plug by hand.
2.
Tighten the cylinder block water drain cock plug to 13 Nm. See Diagram 2
3.
Fill the radiator reservoir assembly with Toyota SLLC engine coolant to the top of the inlet.
Capacity •
Without rear heater 11.2L.
•
With rear heater 13.2L.
Air bleeding and filling 1.
Lift the passenger seat to access the engine. See Diagram 3
2.
Disconnect one of the hoses from
DIAGRAM 4
the “2-way” union located near the throttle body assembly. This is a small steel pipe in the coolant hose specifically used to purge trapped air from the cooling system. See Diagram 3 3.
When air is bled, and engine coolant drains out, reconnect the “2-way” union.
4.
Add coolant through the radiator reservoir assembly filter opening until the coolant reaches the B line, then install the radiator reservoir cap. See Diagram 4
5.
Warm up the engine until the thermostat opens. While the thermostat is open, circulate the coolant for several minutes.
Radiator reservoir location
With the bonnet opened, the radiator reservoir is prominent. Ensure the coolant is at the full mark after the bleeding procedure is complete and the engine has reached operating temperature.
NOTE: If the radiator reservoir assembly is empty immediately after starting the engine, stop the engine. Wait until the engine coolant has cooled, then add more coolant. 6.
Press the radiator hoses by hand several times, then check the engine coolant level. The thermostat opening can be confirmed by pressing the radiator hose by hand and checking when engine coolant begins to flow through it.
7.
Stop the engine and wait until the engine coolant cools down to ambient temperature.
8.
Check the engine coolant level in the radiator reservoir assembly.
9.
Check that the coolant levels are at the “Full” line. If not, adjust the level as required.
10. Using an appropriate tool, pressure-test the cooling system to 137 kPa, inspect for leaks, and repair as required. 11.
Test drive and recheck levels, heater operation and for leaks.
For more information on the HiAce and other Toyota vehicles, log onto VACC MotorTech or call VACC’s TechAdvisory Service.
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SEP 2026
How to test a
Li-ion Battery in an EV or PHEV Following our articles on the basic anatomy of high-voltage batteries and on testing Ni-MH batteries in hybrid vehicles, it is time to tackle the various types of lithium-ion batteries commonly found in plug-in hybrid vehicles (PHEVs) and batteryelectric vehicles (EVs). Many testing procedures can be performed with your diagnostic tool once you know how to interpret the results, giving your customers peace of mind about their electric pride and joy.
types of lithium-ion batteries and their behaviour, you should be able to provide an overview of the battery condition, removing some of the mystery from that expensive, heavy box under the car.
early Nissan Leaf, an MG ZS EV, and a Hyundai Ioniq, which are vehicles the VACC uses to train technicians. All of these vehicles display the HV battery data differently, with various levels of sophistication.
For some background information on battery construction, testing and terminology, please read the following articles:
High-voltage batteries are a mystery to many motorists who are considering buying a PHEV or EV, especially second-hand. They may have concerns about remaining life expectancy and the potential for high replacement costs if the battery fails soon after purchase.
The tests conducted are generic and are based on a combination of OEM procedures and industry experience. The results produced should be enough to give you a good understanding of the battery’s current condition.
Hybrid Battery Testing Ni-MH TechTalk August 2026, page 5988
However, with a diagnostic tool and a basic understanding of the different DIAGRAM 1
High-Voltage batteries – The basics TechTalk July 2026, page 5969
Li-ion Batteries What you need to know In this issue, page 6009
Vehicles we tested
For this article, we have used the OurAuto diagnostic tool with the additional HV package to test an
Pre-checks of the vehicle
Before we start digging into the battery data on the diagnostic tool, there are some checks to perform. The first step is to correctly identify the vehicle you are working on, including the make, model, and series, and whether it is a PHEV or an EV, as there are slightly different procedures for each.
How to access the HV battery testing on the OurAuto diagnostic tool
From the home page of the diagnostic tool, select the ‘Local Diagnose’ icon. Next, select the ‘Battery Pack Detection’ icon.
You will then have to select the make and model.
Finally, select the ’Diagnostic Connector option‘ to view the battery data. The OurAuto Diagnostic tool has a add on pack which can allow you to test high-voltage batteries. Contact our team or scan QR code for the upgrade.
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DIAGRAM 2
Visual inspection of the battery You should inspect the battery and it’s protective plates for obvious damage; signs of impact must be assessed against the manufacturer’s damage inspection criteria.
The information plates on the battery indicate it is a lithiumion battery, including part numbers, nominal voltage, and capacity in amp-hours, but not the type, which is what you need to know for nominal cell voltages.
Check the bottom of the battery pack with a thermal camera for abnormal temperature differences. If found, follow the OEM damageassessment procedure. This camera is part of the EV kit, available to members at a member’s price on VACC’s online marketplace.
marketplace.vacc.com.au
It is handy to know the battery chemistry, such as NMC, NCA, LFP, or one of the many other types, to interpret voltage readings when the car only provides basic data. Unfortunately, this information is rarely stamped on the battery’s exterior case, so check the owner’s manual or the manufacturer’s specifications page for these details. A VIN lookup service or a dealership might provide an original build sheet with these details. See Diagram 2
leaks, and the condition of any orange high-voltage cables. If you have access to a thermal camera, point it at the battery and check for hot spots, which could indicate a problem. See Diagram 2
It is important to check the vehicle’s 12V system and ensure the 12V battery and charging system are in good condition, as this system powers the battery management system (BMS) and the HV battery’s heating and cooling system.
If all the above checks and tests are ok, proceed with the battery test procedures. However, if something does not look quite right, you will have to use your professional judgement to determine if your workshop has the qualifications, skills and equipment to rectify the situation efficiently and safely before proceeding. See Diagram 7
Then, with a compatible diagnostic tool, perform a full vehicle health check or global scan to identify any issues that could affect the HV systems.
Physical damage checks You should visually inspect the high-voltage battery by looking under the car for any obvious signs of impact damage, dents, scrapes, corrosion, damaged or missing bash plates, coolant 6016
Then have a look under the bonnet for anything obviously wrong with the HV components and cables. Then, if applicable, check the HV cooling systems’ coolant level and check for leaks. Next, check the charging port for heat damage, water entry and damaged pins.
starting during the following tests, which could confuse the readings. • Ensure the ambient temperature is comfortable, as extreme heat or cold can affect test results. • Where possible, check the OEM description of the battery to check the number of cells or whether the cells are grouped into blocks.
Battery pack data With your compatible diagnostic tool connected to the vehicle, you can navigate to the BMS and check the live data. The OurAuto diagnostic tool includes a Battery Pack Detection feature that displays battery data. See Diagram 1 However, depending on the vehicle’s software, the battery data can be displayed quite differently, as shown in the diagrams in this article.
Preconditions for battery testing
State of Health (SOH)
• Ensure the HV battery’s state of charge (SOC) is between 50% and 80%. This should allow for accurate results.
Most, but not all, vehicles we tested provided a battery state of health (SOH). The Nissan Leaf did not show SOC or SOH on our tool, but it might on other tools. See Diagram 3
• If the vehicle is a PHEV, ensure that the engine is at operating temperature, then place the vehicle in EV mode if possible. This should prevent the engine from
SOH is a percentage of remaining capacity as calculated by algorithms in the BMS. Using this number provides a quick, easy SEP 2026
DIAGRAM 3
Nissan Leaf battery data
No SOC or SOH
The Nissan Leaf uses laminated lithium-ion pouch cells with a manganese-based cathode chemistry (specifically LMO or NMC, depending on the generation). They have a nominal voltage of 3.7-3.8V. The data above show cell voltages slightly above 4 volts, indicating a high SOC.
Is this voltage delta ok? See Diagram 6
As the battery charges and discharges, the highest and lowest cells should change. If not, this could be a problem.
Make sure that you scroll down the page to inspect the rest of the cells, as only the first 70 are displayed
The Nissan Leaf was groundbreaking in making EVs accessible, but unfortunately, it negatively turned public perception of electric vehicles (EVs) due to its rapid battery degradation, particularly in hot climates. This is due to its reliance on a passive air-cooling system for the HV battery, which was not up to the task, creating fears that EV batteries would inevitably fail and require costly replacements. Most modern EVs use active battery cooling. The Leaf’s battery management system only provides basic data to the diagnostic tool. It doesn’t provide a state of charge (SOC) or state of health (SOH). It displays all 96 cells, shows the maximum and minimum cell voltages, and calculates the voltage difference (delta) for you.
way to assess battery capacity. However, SOH only offers a medium level of accuracy for battery condition, depending on how the percentage is calculated. For a deeper understanding of the battery’s condition and its associated systems, it is recommended to check cell voltages and voltage deltas under various conditions, which will reveal any problem areas. The following tests are generic and can be used on most cars if your diagnostic tool can communicate with the vehicle’s BMS. SEP 2026
Test 1: Battery balance at rest/idle/READY 1.
With the vehicle in Park and the park brake applied, turn the vehicle on or in the “Ready” position.
2. Turn off unnecessary loads: HVAC, demister, lights, seat heaters, etc. 3. Let the battery stabilise for 1–3 minutes 4. Record the SOC, pack voltage, current and battery temperatures 5. Record the highest cell/group voltage and the lowest cell/group voltage
6. Record the voltage delta (voltage difference). If not shown, you will have to calculate the difference yourself. 7. Record the cell/group numbers for the highest and lowest. 8. Save a screenshot or diagnostic report
Test 2: Accessory/load check while stationary 1.
With the vehicle still on / Ready, turn on all loads. HVAC, demister, lights, seat heaters, etc. 6017
2. Watch battery current and pack voltage and see how the results change.
2.
3. Record min/max cell/ group voltage and delta.
Start with moderate SOC, ideally 40–80% and battery temperatures normal.
3.
For PHEVs, ensure that the engine will not start during the test.
4.
While driving at a steady cruise, record a baseline battery reading.
5.
Record min/max cell/ group voltage, delta, current and temperature for each of the following:
4. Save a screenshot or diagnostic report
5. Turn loads off and watch how the battery recovers
NOTE: This is not a substitute for a road-load test, as a stationary accessory load test may be too small an amperage draw to reveal a weak HV battery group.
Test 3: Controlled acceleration EV-mode load test 1.
Find a quiet road for a test drive and bring an assistant. One to drive the car, the other to operate the diagnostic tool.
DIAGRAM 4
(a) a moderate acceleration, performed when safe to do so; (b) a sustained load such as a hill climb or steady road speed. Record the battery data.
Test 4: Regenerative braking test 1.
Start with moderate SOC, ideally 40–80%. If SOC is too high, regenerative braking might be limited.
2.
Some vehicles have multiple regenerative braking settings; if possible, set it to the highest.
3.
While driving at a steady cruise, record a baseline battery reading.
4.
Then release the accelerator and record the battery data.
Test 5: Controlled charge test 1.
Connect the diagnostic tool before charging.
2.
Start with moderate SOC, ideally 40–80%.
2021 MG ZS EV
As the battery charges and discharges, the highest and lowest cell numbers should change. If one cell remains and is the same, this could be a problem.
As the state of charge is displayed at 93.7% and the cell voltages are slightly over 4 volts, this aligns with the high SOC. If you subtract the highest and lowest voltages as shown above, you get a 0.02-volt (20 mV) difference, or delta. See Diagram 6 The MG ZS EV has a more sophisticated BMS that displays SOC and SOH, giving you a quick idea of the battery condition. Unfortunately, it will not show you the individual cells and their voltages graphically. You can scroll down the data list to find the maximum and minimum cell voltages. You will then have to do your own maths to work out the voltage delta. From 2020 to 2021, the ZS uses NMC prismatic cells with a nominal voltage of 3.6V-3.7V. From 2022 onward, the ZS standard-range models switched to an LFP cell with a nominal voltage of 3.2V; the long-range models still use NMC cells.
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DIAGRAM 5
Is this voltage delta ok? See Diagram 6
2018 Hyundai Ioniq AE
The Hyundai Ioniq EV uses 96 NMC battery cells. The BMS provides SOH and SOC readings, which makes interpreting the data easier. The SOC is at 50%, which aligns with the nominal voltage range of the NMC cells, 3.6-3.7 volts. The displayed voltage difference of 0.0 V indicates excellent balance between the monitored cell groups under the test conditions. The vehicle also reports an SOH of 100%, suggesting the battery management system considers the battery to be in very good condition. The 2018 Hyundai Ioniq (AE series) is a five-door hatchback notable for being the first vehicle globally to offer three distinct electrified powertrains on a single, dedicated platform: hybrid (HEV), plug-in hybrid (PHEV) and electric (BEV). Designed specifically to compete directly with the Toyota Prius, the Ioniq prioritises conventional, user-friendly styling and a normal driving feel rather than an overly eccentric look.
3.
4.
Connect the vehicle to a knowngood AC charger (Level 1 or Level 2). Use the portable charging lead supplied with the vehicle known as electric vehicle supply equipment (EVSE) - or another AC wall charger. Don’t use a DC fast charger, as this will bypass the onboard charger and could add unwanted variables into the test results. Also, not all cars are compatible with fast charging. However, DC chargers can be used to test temperature sensors as they heat the battery pack quickly. Once charging begins, record charge current, pack voltage, SOC and battery temperature SEP 2026
5.
Graph the highest and lowest cell/group voltage and watch the voltage delta as SOC rises.
6.
Record if any group reaches high voltage before the others.
How to interpret the results Once these tests are complete, you can compare the results and see if any cells or groups of cells show abnormal results. For a battery pack in good condition, there should be a low-voltage delta at rest, and it should not increase significantly under light or heavy loads. There should not be any spikes in the delta reading during regenerative braking or charging. The highest and lowest cell or cellgroup positions may change as
state of charge and load conditions change, which is a good sign. If a cell or group repeatedly remains an outlier under comparable test conditions, it should be investigated further.
Cell imbalance / voltage delta range There is no universal voltage-delta value that makes every EV or PHEV battery “unserviceable”. OEM limits vary by vehicle, chemistry, BMS strategy, SOC, temperature and whether the reading is taken at rest, during charge, under load or during regenerative braking. The following information is a screening guide for interpreting diagnostic tool data; they are not OEM pass/ fail limits. See Diagram 6 6019
DIAGRAM 6
Voltage Delta diagnostic guide for Li-ion battery packs
Delta
Interpretation
0-10 mV
Ok, very low voltage difference
>10-20 mV
Acceptable, generally small voltage difference
>20-40 mV >40 mV
Suspect, elevated voltage difference
Recommended Action
No immediate concern. Continue normal assessment and compare with OEM information where available. Compare results with OEM specifications and monitor for consistency. Repeat testing under controlled conditions and monitor for changes over time.
Investigate further using the OEM Significant voltage diagnostic procedure and additional difference battery diagnostics as required.
NOTE: These figures are generic screening estimates only; if a fault is suspected, the OEM test procedures and specifications should be used to confirm a diagnosis.
For some vehicles with LFP batteries, the manufacturer may recommend periodic charging to 100% to assist SOC calibration and cell balancing. Always follow the vehicle manufacturer’s charging instructions. If the delta results are not great, complete a full charge to 100% and retest to see if it improves. Any large voltage delta, repeated outlier cell or group compared with
the remainder of the pack, or a delta that increases rapidly under load should be investigated using the OEM battery diagnostic procedure.
Conclusion
It is possible to make a reasonable estimate of the current battery condition across a wide range of EVs and PHEVs if your diagnostic tool can access data from the battery management system.
DIAGRAM 7
WARNING : High-voltage training To safely depower and reinitialise battery electric vehicles and to access HV repair information, technicians must complete the following course. Battery electric vehicle training AURETH101 - Depower and reinitialise battery electric vehicles If the tests in this article indicate that the HV battery (RESS) requires replacement or repair, applicable OEM procedures, workplace safety controls and additional competencies should be acquired for a safe and reliable repair. For further information, contact us at (03) 9829 1130 or email info@vaccsdc.com.au vaccsdc.com.au/automotive-electric-vehicle-training/
We have described the tests you can perform under various load and charging conditions. It is now up to you to decide whether to offer some or all of these tests as a pre-purchase inspection or as a check included in your customers’ regular service to monitor the battery’s condition. Research increasingly indicates that the service life of modern Li-ion batteries is far longer than first predicted. Using your diagnostic tool is an excellent way to provide an overview of the battery condition, giving customers some peace of mind or indicating that more thorough diagnostic procedures are required. For more information about vehicles with HV systems, log onto VACC MotorTech or call VACC’s TechAdvisory Service.
A big thank you to Joel and the Infinitev team for their assistance with this article. For diagnostic assistance with HV battery issues, contact:
infinitev.au 0439 360 360
Feedback
techtalk@vacc.com.au 03 9829 1292
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