Adrian Brown

If i get a used ecu will this need to be programmed into my car; or can i just swap them over. 
Thanks

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 

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. 

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