2010 Audi A4 Avant - Sudden Total Power Loss

We just bought a brand new A4 Avant–less than 300 miles on it. Last week, we were making a simple left turn from a side road onto a two-lane highway with a 50 mph speed limit. Initially, we accelerated away from the stop sign normally, but about a car length into our turn, we heard a loud clunk and simultaneously completely lost engine power. I took my foot completely off the gas, thinking I had to re-start the engine, when I realized the engine had not shut off. I put my foot back on the gas, the engine responded, and I was able to pull to the side of the road.I estimate we were traveling 20-30 mph when it happened.



The road was dry. There was no unusual gravel or dirt on the road. We did not hit or run over anything. The highway we were merging onto was essentially level.



The dealership says the engine codes tell them nothing is wrong and nothing happened. Naturally, they have been unable to reproduce the effect. Their current theory is that I had one foot on the brake and the other on the gas–which just isn’t so. I would appreciate any thoughts as to what might have caused this.

You pulled to the side of the road. The engine was still running; but, it wasn’t driving the car. How did you get to the dealer?
Keep records of your complaints to the dealer (names, dates, who said what, what was said). If this happens a few more times, and you take it to the dealer (still recording), and it isn’t fixed, invoke your state’s LEMON LAW.
Too, contact Audi America, and the National Highway Safety Commission, and file complaints. If you don’t get your complaint recorded by those agencies, your complaint doesn’t exist.

One tire may have lost traction (grit on the road perhaps) and that cut the power as part of the traction control system. These transitions aren’t always smooth. That is possible reason if car is now “normal”.

The other issue could be the car went into “limp” mode for some reason. Usually this happens if the trans tries to go into 2 different gears at the same time. Say you started to accelerate and then pulled off the gas for an instant. The trans might have been going to 2nd gear and then with less pressure on the gas was going to 3rd, but more pressure back on the gas sent it back to 2nd and it just got mixed signals from the computer and shut down in confusion.

A limp mode should leave a code however, but perhaps it take repeat incidents to throw a code.

Disconcerting in a new car.

Thank you. That may explain the event, although, as you note, it may not quite explain the lack of a code. I’ve heard of “limp” mode, but I don’t really know what it is. Would you expect the car to stay in limp mode? After we regained power, we were able to drive normally.

I appreciate your thoughts. Looking at my original post, I may not have been clear. The power loss was momentary, a couple seconds at most. Once I took my foot off the gas then put it back on, we regained normal power and the car has been driving fine ever since.

I’ve gone into “limp” mode on one car and it was reset when turning off the key and then restarting the car. Think of it as an electronic burb. If you have a real problem then it will stay in limp mode and not reset with turning the car off and back on again.

If this problem occurs again then there maybe a problem requiring service. I’d note the date and particulars in your service log on the car and hope for the best for now.

I have run into this problem a couple of times. The “loud clunk” may be the key. I know this is out in left field but here goes: Both of the situations that I encountered had to do with batteries. In both cases the batteries had shifted, one had no battery hold down and the other was simply loose. The batteries had slid over and contacted metal from the hood. I know this vehicle is a lot newer but check the battery hold down and make sure the battery is secure. Look around the battery area to locate any signs of arcing against metal. One vehicle was my mother-inlaws brand new 2001 Mercury Sable and the other was my used Silverado 3 door pickup. Some numbskull had removed the battery hold down for some reason or other.

Why don’t you repeat the turn and press both the gas and the brake at the same time to see if the vehicle reacts the same way as when the problem happened? If it doesn’t then you can go back to the dealer and explain that it couldn’t have been the brake override. Otherwise, you might have to reconsider their theory.

Thanks. I have done the gas and brake at the same time test (with the loaner car we have–our car is at the dealership as they try to figure out what’s wrong) and informed the dealership that the effect was not at all the same (the car does eventually come to a stop, but it is nothing like the sudden total power loss we experienced). In my opinion, that theory has been put to rest, but I’ve yet to hear a new theory from the dealership.