cis8vgti

The battery in my 2001 A6 died during the recent storm. I hooked up the jump box positive and negative in reverse in errror. Small fire on battery terminal was the clue.

Anyway, now car wll not start. I have a nice blue spark on plug #1. No radio, will not even come on. I can not make a connection with the car with VAG-COM. I used it on two other cars 5 minutes later with no issues.

I went through all the fuses on the driver side panel. I hoping this car has a ECU relay. if not, I think I fried my ECU.

Airbag

uh ohhh that does NOT sound good.....

Think your ECU is fried but don't have a specific answer. did you try taking the battery out all together , charging it and putting it back in ? there may be an ECU relay and i have the same car if it is the 2.8 so i will check mine.
does it turn over but just not fire ? or does absolutely nothing. ? i wonder if there is a fuseable link somewhere that can be replaced.

cis8vgti

Yes, the car does turn over. It sounds like it want to catch but it does not.

I did a search on A.W. and I found someting about a 'ECU power relay'. I'm not sure if this relay is under dash near the pedals or under the hood. Below is what a fellow member posted:

between the coolant reservoir and the middle of the steering wheel. Follow that line towards the steering wheel. In the gap between the firewall and the engine compartment, there's a flat black plastic "box" about the size of a few VHS platic cases stacked on top of one another. It's in there.

The description of the location is a little strange but I'm going to take a peak. My car is a 2.8 30V V6.

cis8vgti

I do not know what was up with the cryptic message posted by another vensor, but there is a relay and giant 40A fuse in a plastic box that holds the ECU.

The 40A fuse is not blown. Two of the connectors on the relay is dark. Dark from being old or blown, who knows. But I'm going to start with this relay.

Does anyone know if there are more relays or fuses associated with the ECU?

socalclimber

There looks to be a 15A fuse (fuse #5) next to the ECU relay (relay #3).

cis8vgti

Thanks for the post!

Is this relay panel located under the dash near the driver's leg?

socalclimber

No, this is the one in plenum near brake master cyl.

Airbag

you have to get under the hood, take the black plastic plenum cover off and then i think itis 3 or 4 10mm bolt heads to get the cover off.

cis8vgti

In my car, the black plastic box next to the brake reservoir only has the ECU, relay #214 and a giant 40A orange fuse, nothing else. if my car has these relays/fuses as depicted in the PDF attached file, this panel must be someplace else.

socalclimber

I sent you a PM with a link to more fuse/relay info. Did you see that? Maybe what's in the C5 Bentley Service manual is generalized and doesn't cover all models or the early ones?

Looked into wiring diagram for the 2001 2.8 (ATQ), make sure these are good at main fuse panel (driver's side):

Fuse 29 (30A) Power Output Stage for coils
Fuse 32 (20A) Fuel injectors + ECU
Fuse 34 (15A) Fuel pump relay

I think for that matter, I would check every fuse with an ohm meter just to make sure they're good.