Airbag Deployed/ Car won't start
 

Hi guys, first post.

I just acquired an '08 Audi TT Quatro from a friend of my wife's who was in an accident. There is damage to the driver side door and rocker panel as well as into the rear quarter. The driver side seat Airbag deployed in the accident. My question is, when this car gets in an accident and an airbag deploys, should this cause the engine to not start?

Pulled a few codes, but none having anything to do with the airbag that I can tell:

P0491
Check fuse for secondary air pump
P0492
Check hoses for SAP relay

and U0100
Something to do with ECU communication?

Any help would be greatly appreciated.

May have just found the problem while digging around by the battery. It appears there is some sort of sensor or monitor at the positive battery connection. Found the part in a diagram, and it costs $260. Anyone know if this can be reset or if it must be replaced?

So this was the problem. I was able to bypass it and start the engine. Still hoping that this part can be reset or fixed so I don't have to buy a new one.

Airbags deployed. Q7 won't start
 

Having just been through hell and back trying to get my Q7 to run after an airbag deployment, I thought I would share my experience. My Audi hit a large pothole in a field, on a horse farm, in Lexington. Passenger door airbag deployed although there is no damage and there was no collision. Afterward, no start. The culprit is this nifty little over engineered device called the battery interrupt igniter. The battery interrupt igniter blows a fuse after airbag deployment so the car doesn't catch on fire, because an airbag only deploys after an accident ((or a pothole) read sarcasm) so naturally, since most cars catch on fire after an accident (more sarcasm), someone found a way to fix the problem. Took it to an import shop. They didn't know. Went to Audi dealer. They didn't know but when we explained what we thought the problem might be, they ordered a battery control unit for us to take back to the shop. Wrong part. So, finally the import shop guys figured it out. Incidentally, body shops know what to do because they deal with the aftermath of collisions and airbag deployments and blown battery interrupt igniter parts routinely but I did not need any body work, just needed my vehicle to start so I went to a mechanic. On day 7, out of sheer desperation, I called Bedford Collision and the nice guy there knew exactly what the problem was and called me back with part number I needed in less than 30 minutes. Even after I explained my car was out of state he graciously helped me). The techs at Audi did not offer to help much. Just told my shop (and me) to bring the car back to them. Naturally, they said my airbag needed to be replaced because now none of my airbags will work until the blown one is replaced and the computer is reset. But that is not required to get up and running. My battery interrupt igniter is replaced and my Q7 is running. Only took 7 days! I am hoping that my Q7 doesn't get mad that I did not yet replace the passenger airbag and decide to blow the fuse again. Audi guys said that would not happen. We will see. But not for a while. My Q7 is in Kentucky and I am 700 miles away because I had to go back to work, without my car, because someone at Audi central decided that it is not within my rights as owner of the vehicle to decide if it can still run after the airbag goes off. Mandatory shutdown. Hmmmm.