How to know if faulty ecu

A6 All/ S6 All
#1

Is there a way to determine if my ecu is faulty in place of a bad ground for exemple in my case?

Random stall only when car is at operating temperature and idling, voltage doesnt drop, stall is most likely because ecu loses communication with its sensors during this episode.

I forgot to mention that when I had my alternator issue, its the voltage regulator that died, meaning that I could idle the car, but the moment my rev climbed, the voltage would too at the same time. Before I realised that, ive seen the voltage climb to 16v and even 18v once. I thought I was lucky and didnt fry anything since after replacing it, no problems occured electronically… ´til now with this. Did I fry a connection but not completely and it only fails when car is hot and idling??? Im shit with electronics man

#2

And in the ECM 1 faults, theres the ECM 2 implausible signal. Is it safe to assume the ECM2 would be the faulty one?

If so, which one of two is the ECM 2? Left or right?

IMG_0675
IMG_06752142×2856 1.91 MB

#3

SO from what I remember - The far left is 1 and in bottom one is 2… BUT the S8 and S6 I think might have it swapped.

What you can do is look on the bosh label. There’s going to be a number on the tag. It’s an actual number your number for the top one looks like 149 and the bottom looks like it’s 148 or 146… From what I remember that makes the lower ECU 1 and the upper far left ECU 2.

You can obviously unplug them 1 at a time and then try to log in with your vag com and see what one can’t be found.

1 Like