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Bryan, Technician
Category: Audi
Satisfied Customers: 410
Experience:  Four years experience diagnosing and repairing Audi vehicles
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Audi A6 Quattro with 3.0L engine

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Have an 2002 Audi A6 Quattro with 3.0L engine @ 122,000 miles. All maintenance done. Issue now is that the ESP light will come on (flashes and or stays on when driving - usually at low speeds and often after turning) -- then the ABS system "takes over" all by itself. The ABS light does not come on. Mechanic said that battery reservoir drain was clogged and thought that water was splashing out onto the computer, causing miscommunication/faulty signal being sent to ABS problem. However, this has now occurred again (twice today) after the water was drained out and the drain line was cleared. This time, the car almost brought itself to a complete stop while I was driving it. So, I would like to now if someone actually KNOWS what is going on with this car ...


My name isXXXXX will be glad to assist you today in answering your questions.


Half the problem is the brake light switch the other half is a bad ABS module, Check out they can rebuild your ABS module and warranty it for a reasonable price. this is a common problem on your vehicle.


To make sure this is the only issue, I would ask that you have the codes pulled, its a slight chance but just want to make sure you don't have any codes in the engine computer for the gas pedal sensors


Best regards,


Customer: replied 4 years ago.

The mechanic said that there were no visible codes; likewise he was unable to duplicate this event (even though he had the car for a week). The ESP light doesn't stay lit when you turn the car on (meaning that when you turn it off and turn it back on, the ESP light doesn't necessarily come on and stay lit at that time. It just comes on whenever the mood strikes it and when that happens, the ABS thing almost always happens right afterward (if it is going to happen that time). Unfortunately, I was able to duplicate this event this morning while I was driving. So, my main questions regarding your response are 1) Is it possible that there are no codes being reported but the ABS module is bad anyway? 2) Is it possible that the whole issue is a byproduct of a faulty brake light switch? 3) If the gas pedal sensors are bad, would this for sure show up in the codes?

Yes the brake light switch could cause both issues. I would replace that first and then see if the issue continues.

Yes if the pedal position sensors were bad there would be codes, there should have been a code for the brake light switch in the instrument cluster, but I would guess your mechanic did not think to check that module

Bryan and 4 other Audi Specialists are ready to help you
Customer: replied 4 years ago.

Thank you for your time and advice.