CASE STUDY
Case study by Gareth Davies AAE FIMI, Euro Performance Vehicle: 2017 Audi A6 All road 3.0 TDi Quattro CRTD engine code Problem: Lack of power, poor running, no warning lights on the dashboard
A mystery involving a remap history Being a brand specialist can make life somewhat easier in the workshop. It’s only natural you will see a higher repetition of cars presenting the same faults and you can often go through periods saying, “it looks like it’s another one of those”. These are not born out of complacency and applying the correct process will always apply. However, on the other hand, there are an increasing number of occasions where you are sought out by the consumer because no one else has been able to help. No, we don’t survive as soldiers of fortune because we escaped from a high security military stockade for crimes we didn’t commit… We exist because of our backgrounds, our chosen brand specialism or, maybe, just because we have a reputation for being able to help, when seemingly others can’t. In this case study, the vehicle in question was a 2017 Audi A6 All road 3.0 TDi Quattro, CRTD engine code. It was booked in with us after a visit to the local Audi dealership. At the point of enquiring, I was asked by a front of house colleague if we were able to help. The dealer had advised the customer because the car had been re-mapped (a process whereby the engine ECU software is modified to improve various factors such as performance and fuel efficiency) they would not be able to help. I agreed this would be something we could help with, and he was duly booked in. Ten days later the vehicle came in and the customer completed the fault assessment questionnaire. The notes described a lack of power, poor running, but no warning lights on the dashboard. I began with busting out the big and shinier laptop than other independents (ODIS) – after all, that’s usually why they end up with us specialists, purely for a better laptop… Whilst it was loading up the vehicle ID and carrying out a fault code scan of the car, the customer had kindly left some documentation with his questionnaire from his dealer visit. The logs showed communication between a technician and the mother land (Milton Keynes, the halfway house to full blown mother land). They had requested technical help as they were unable to shed light on the issue. The technician was advised the engine ECU software was modified and as a result, this would need to be corrected before proceeding further. It’s likely that a commercial decision was made by the dealer not to move forward, which is fair enough. If it’s not their type of work, that’s understandable. 24
We had completed the scan and as far as fault code entries went, there wasn’t much to go on. There was a sporadic entry in air suspension for ‘compressor shut off’, the type and nature of fault is what is left behind after jacking/wheel change mode, and there were no issues visually with the air suspension set up. It was apparent quite quickly that the car was very unhappy. The technician who had kindly brought the vehicle around into the workshop for me whilst I had been finishing talking to a customer, reported in good old fashioned Welsh terms ‘that car is proper unhappy butt’. I found this interesting, given at this point I hadn’t run the engine, merely connected a battery support unit and was using ignition only. I started the engine. It was apparent very quickly, he wasn’t lying. The vehicle would start, it took a little longer than normal to catch, and when it did, it ran very badly and cut out almost immediately. If you persevered a few times, and then introduced some throttle whilst running, it would begin to improve to a steady(ish) idle. Rarely would you expect such a dramatic and obvious presented symptom, without any fault code entries, of any kind. Most importantly, ones that may indicate as to why the engine was so grossly unhappy and cuts out. Basic live data checks revealed nothing concerning; fuel pressure was a plenty and a relative compression check was also acceptable. Before getting too deep, I consulted technical service bulletins. There were a lot, but none that directly fitted my symptoms, particularly with no DTC entries. Now, I suspect some of you are reading this, and like the pantomime ‘he’s behind you,’ are screaming “It’s the map, it’s the map!” Well okay, there are factors in the map that could be attributing to the issue, but some good datum points I always like to check before assuming anything would be: