Trav-BC

Hi all.

New to Audi, have been appreciating all the information here.

Recently my wife's new to us q7 just died. No crank, and a few errors on the dash. Based on some of the information here I replaced the battery and hoped for it to be that simple. No change at all. It appears to be the ECM that has failed. I get no communication with it. When I scan the system I get lots of various errors.

Does anyone have experience with getting a ECM from ebay motors? I'm not adverse to going to the dealer if I have to. But $300-400 is better than like $2000+. Also concerned about the fact most units on ebay motors are from the USA and the vehicle is Canadian.

Thanks.

'10Q7TDI_Prestige'

Be sure you use a VAGCOM type scan tool, otherwise it won't be able to read fault codes at the control module level, which should be plenty on a 2009. Realistically, the VCDS VAGCOM is probably what you need on the older car to help you navigate through diagnosis and repairs that other VAGCOM scan tools aren't optimized for. The ECU swap will almost certainly require the part to be security coded to the car by an Audi dealer or shop with the ODIS system, which connects to the mother-ship in Germany. You also may find that the ECU problem is due to water damage from blocked drain tubes in the plenum beneath the windshield, which are common issue on this car, as are other water drain blockages and leaks. Do your research.

A used ECM is certainly cheaper, but be sure to check for the latest part # revision for your car's engine...same part #, but the suffix on it changes to indicate it's a different/newer/updated part, etc. So if your ECU is a 'C' suffix part# and the most current for your car is a 'G' suffix part#, then you want to try to locate one of the later suffix parts, which are less old, and hopefully be more reliable than getting one from same year model as yours was built in, etc. Try to locate one with at least some limited warranty on the ECU if buying a used one.

Here's an overview:

Trav-BC

Well I took it in because I was starting to feel out of my depth of understanding.
From the Audi tech, ECM has no communication to some of the other modules. Still no diagnosis, they say it will have to be connected to different system scanner and be scanned for 4-8Hr or more to find out what is wrong.
Quoted about $4200 (Cad) for a new ECM, but they cant confirm if that is the issue or the only issue. They say there was rodent droppings found in the engine bay area. What are the odds of if being a chewed harness? Is that even better or worse. Anyone have experience with chewed wiring and the problems from it?
I'm at a loss, we have had the car for a month. Paid a bit high privately because it was well taken care of. When it was running it was fabulous.
When do you pull the pin and take a big loss selling a parts car?

B6-3.0L

It could be chewed up wires, that happens on occasion. That’s not too hard to repair. Also, the cowl on the Q7 can collect water if the two drains are clogged. The ECU and power distribution block are up there. A waterlogged ECU/wiring could cause your problem.