2007 Q7 dead...HELP!

[davisead]

Have a 2007 Q7 3.6 Premium that died a couple of days ago. No power at all...turn the key (which is now stuck in the ignition) and nothing happens! No lights, interior or exterior, no bells, no whistles. Attempted to jump it...still nothing.

I'm not certain exactly what occurred prior to it dying, but what I did find out is my idiot cousin and his buddy tried to jump it. They did not turn the "jumping" vehicle off prior to connecting the cables and "cannot recall" the order the cables were connected. I am willing to bet money, it was not the correct order. Before they tried to jump it the exterior lights worked, the dash board lights came on, the MMI worked, the tailgate opened (the jumper cables stay in the storage compartment) and I had driven it 2 days prior without issue.

When I returned and was informed of the situation, I decided to try jumping it at the battery directly... since neither of them knew where the battery was. While attaching the cables I unknowingly moved the ones laying on the ground and they sparked! This led me believe the battery still had a charge, so I removed them and started checking fuses and relays and stumbled upon the battery current sensor (battery isolation igniter). Does anyone know if this sensor will prevent the vehicle from starting, if the battery is overloaded due to improper jumping? If so, how can I test it? I also found the Motronic Current Supply relays voltage was low (C2 in the engine compartment fuse box). Since there is no power flowing, I am not able to scan for any codes. Any suggestions/advice, other than taking it to the dealer, would be greatly appreciated!

[Pothole]

Per Audi you should jump through the posts under the hood. That way the battery maintenance manager knows what is going on. Jumping direct to the battery goes around the cars electronics.

The cables sparked from the Q7's battery? There maybe juice left in the battery but not enough to start the car.

Do you have a battery charger? Plug that in and verify it is taking and holding a charge. You may have killed the battery and need to replace it but need to start there before diving into deeper things.

[davisead]

There was some juice initially, but I think it is dead now. I pulled the battery out and taking to see if it can be charged or needs to be replaced. I believe there was/is something draining the battery, prior to this issue, but it would always start when I jumped it. I always use the post under the hood to jump it or jump another vehicle. I took it to get the oil changed some years ago while I was traveling and it wouldn't start. They tried jumping it at the post and it still wouldn't start, so the guy lifted the seat and jumped it directly at the battery and she started right up. I replaced the battery afterwards and have not had any issues since.

Will see what happens when I take it to get charged. I purchased this battery in 2017, I checked to see how long it had been since I replaced the other one. I'm certain the previous battery was more than 3 years old when I replaced it. Wish me luck!