what2be

That's where I got th this replacement ECU. I bought them for Mercedes and they were about 120 bucks I bought bought them for an S4 which was only 100 bucks but the Q7 is few and far between especially TDI ones, I paid $500usd for it. I'm not sure if they're just that hard to find or if that many of them get water intrusion or go bad

Yes, that was what he was referring to by his statement of it starting for a few seconds and dying, that is classic immobilizer behavior and exactly what I experienced when I replaced the ECU on a 2010 S4. His point was that since it wont start and die, its not the ECU, but Im not sure I buy that. Anyway, im going down there this morning to run some tests and see where im at. Ill post my results. .

If i replace the ECU with a used one from the same model car, will the car start and die a few seconds later until I get it reprogrammed? I bought a used ECU and swapped it out but when I took it to the shop they told me the ECU couldnt be the problem because it did the same thing the old ecu did (crank but no start). He said if it was the ECU the car would start and then die a few seconds later until he reprogrammed it. Is this correct?

It has the 3.0 and I believe it had 9 terminals it was just missing one. It keeps coming up with this: Basic OBD2: P0683 (Permanent) (Pending) (Confirmed) - Glow Plug Control Module to PCM Communication Circuit Engine: 14625 - Glow Plug Control Module 1 to PCM Communication Circuit I checked three of the glow plugs cylinders 4,5,6 and they all tested fine but the boots were so brittle they broke off and on the number five glow plug ( the pressurized one) it came apart and I tried putting it back together but now the car won't start the glow plug icon just flashes so now I need to go buy another pressure glow plug ($170) . I think I'm going to replace the harness for the number 2 and 5 glow plugs as well, its only $85 but it doesn't look like a very fun job to put in. I've got an ABS pressure error as well, from what I've researched sounds like the ABS pumps bad but if that voltage on the glow plug controller is really supposed to be 3.4 v and not 12 v then obviously the ECU has problems

2012 Q7 TDI Prestige In alldata they list the steps to test the glow plug controller with a volt meter, but they list one terminal (Terminal 10 , relay terminal ST) as 3.44 volts, mine is 12v. They also list terminal 9 (relay terminal D1) as 10.74 volts, but my glow plug controller does not have a terminal 10 on it. Is this correct information or am I OK?