Adrian Brown Posted August 5, 2021 Share Posted August 5, 2021 Audi A3 2.0 TDI 170 BHP year 2010 In hot sunny weather (say +25 degrees) the car will not start. It does one of 2 things. 1/ instrument cluster lights up and then goes dead (there is power everywhere else; ie; windows, lights, radio etc etc). 2/ starts and then cuts out within 3 minutes. The car will not start afterwards. When the temperature outside cools it starts and runs perfectly. It runs all winter perfectly and passes MOT’s with no advisories. Parts replaced so far; battery; ignition switch; starter motor; genuine Audi instrument cluster; still not resolved issue. Audi UK have had car twice (they replaced cluster) and nothing comes up on their computer. Anyone had this issue? I am able to do most things but dont know what to do next. Many thanks; Adrian Quote Link to comment Share on other sites More sharing options...
cliffcoggin Posted August 5, 2021 Share Posted August 5, 2021 Adrian. My first thought was the instrument cluster but as you have had that changed I am at a loss to think what else it could be. Did Audi have any suggestions, or did the problem not happen while the car was in their hands? Sadly the reliance on diagnostic computers has eliminated the human brain as a means of tracing car faults. Quote Link to comment Share on other sites More sharing options...
Adrian Brown Posted August 5, 2021 Author Share Posted August 5, 2021 Audi have no idea either. Because the diagnostic did not reveal anything they are as confused as me. I have shown them videos of the fault. I thought they might have a data base centrally they could access; but no. Thanks for your time. Quote Link to comment Share on other sites More sharing options...
cliffcoggin Posted August 5, 2021 Share Posted August 5, 2021 Thinking further on the matter, perhaps speculating further would be a better description, if the problem is outside temperature dependant I would investigate how and where that temperature sensor affects the ECU. I reckon there must be an temperature input to the ECU so that it can compensate for ambient air temp variation, but the details of how that circuit operates are beyond me. I suggest an auto electrical specialist would be the best option at the moment, because I have been distinctly unimpressed by reports I have read on this forum regarding the diagnostic abilities of even Audi main dealers. As I said before, if the computer says no, Audi are stumped. Quote Link to comment Share on other sites More sharing options...
Adrian Brown Posted August 5, 2021 Author Share Posted August 5, 2021 Great point; i will investigate this idea. Fault ONLY happens when its hot and sunny and car is always outside. I wonder if it would happen if parked in garage and then taken outside into hot sunshine ( i expect not). The dash top is too hot to touch when outside is +25 degrees (much hotter in car). I think something under dash is affected by the heat and therefore causes issue. I note the ecu is located under the wipers at front of windscreen. Does this supply 12volt to the cluster? As stated if i go back in the evening when cooler; all starts as if nothing happened. Stopped calling RAC as they are unable to get it going. Thanks for reading Quote Link to comment Share on other sites More sharing options...
cliffcoggin Posted August 5, 2021 Share Posted August 5, 2021 Please do let us know the outcome. The information would be invaluable for future reference. Quote Link to comment Share on other sites More sharing options...
audia4b5kev Posted August 5, 2021 Share Posted August 5, 2021 ECU BUD MATE HAD SAME BOTHER KEV Quote Link to comment Share on other sites More sharing options...
Adrian Brown Posted August 8, 2021 Author Share Posted August 8, 2021 If i get a used ecu will this need to be programmed into my car; or can i just swap them over. Thanks Quote Link to comment Share on other sites More sharing options...
audia4b5kev Posted August 8, 2021 Share Posted August 8, 2021 as long as you get every thing it is plug and play kev Quote Link to comment Share on other sites More sharing options...
alesandro197 Posted April 3 Share Posted April 3 I have some problem Audi A3 19 TDI 2009 Help me. Quote Link to comment Share on other sites More sharing options...
Steve Q Posted April 3 Share Posted April 3 2 hours ago, alesandro197 said: I have some problem Audi A3 19 TDI 2009 Help me. Have you done a diagnostic check to see if any fault codes flag up? Quote Link to comment Share on other sites More sharing options...
alesandro197 Posted April 3 Share Posted April 3 yes but when it gives me the problem that it is hot it gives me multiple errors Quote Link to comment Share on other sites More sharing options...
alesandro197 Posted April 3 Share Posted April 3 Sorry for my english Quote Link to comment Share on other sites More sharing options...
Steve Q Posted April 3 Share Posted April 3 2 hours ago, alesandro197 said: yes but when it gives me the problem that it is hot it gives me multiple errors What are the errors? You're English is good don't worry🙂 if you're getting various codes could there be an issue with the battery? a failing battery can throw up all sorts of electrical problems. If the battery is 5-7 years old or older then it could be starting to fail. I'd recommend a battery test. Quote Link to comment Share on other sites More sharing options...
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