I am not sure if this is the right place because I do not know what is B5, 6, 7, etc. I drive a boring Camry.

However, my wife drives 2000 A4, 2.8 Quattro. Several weeks ago the ABS in her car started flashing, followed by the Break lights. It usually happens for a few seconds and then the lights go off. Today they stayed on for about 5-10 minutes while she was driving.

Before taking the car to service, I would like to have some understanding of what is going on.

If this is not the right forum, please point me to the proper place.

Thanks,

BerDov

My 97 did that, but all four of my brakes were locking up also. The brake lights would stay lit until I pulled back on the brake pedal. I changed my master cylinder and flushed my system and every thing is working right now. You can always find someone with the VAG-COM and scan it. Thats what I did.

I just got some (important?) details from my wife.

Today, the ABS then Brake lights came on when she turned the ignition on. I assume a problem was detected during the initial self-check. Then after some moments/minutes the ABS light went off, but the Break light stayed solid on for about 10 min of highway driving + 1 min street driving; then it went off.

I sense it’s the ABS problem, but want to rule out the breaks. I drove the car for about 20 min last weekend and did not notice anything wrong/unusual/new when pressing the brake pedal. Both light did come on for about 1-3 sec in the middle of highway driving.

This is commonly the ABS control module malfunctioning. If the fault codes come up with nothing than its more than likely the module. Its more common on the A6 however, there are companies that can re-build the module which is much cheaper than buying a new one.

P.S. you have a B5 A4, so your in the right forum. B6 is 02-05, B7 is 06+

Thank you!

I assume that fault codes come up with something or nothing during a diagnostic check. I cannot perform it myself. It means that the car has to go to a dealer. Right?

Since you mention re-building the ABS control module, how accessible is it?

Please educate me on the naming convention. All I know is that the car is A4, 2.8 Quattro. What is B-5?

Lastly, can my wife be sure that it’s not the breaks and she will not loose control, especially on the highway? She is a careful but not a timid driver.

I am not asking for a guarantee and will not hold anybody liable for anything. Common sense reply is all that is needed.

Thanks.

I assume that fault codes come up with something or nothing during a diagnostic check. I cannot perform it myself. It means that the car has to go to a dealer. Right?
No. Autozone does free diagnostics scans. Once you get the codes, post them here and we should be able to tell you exactly what's wrong.

Since you mention re-building the ABS control module, how accessible is it?
It's a bit of a pain. You have to take off the drivers side wheel, remove the wheel well liner, move the wiper fluid resevior, then turn your arm into a snake to get to the bolts holding in the module. It's not very difficult, but it may take some time. You can get it rebuilt for about $200. what happens is the seal goes over time and moisture corrodes the circuit board.

ModuleMaster has a great video instruction located here- http://modulemaster.com/audiabsremoval.html

Please educate me on the naming convention. All I know is that the car is A4, 2.8 Quattro. What is B-5?
All A4's are B series. The year determines the number. 1996-2001 are B5, 2002-2005 are B6, and 2005.5-Current are B7.

Lastly, can my wife be sure that it’s not the breaks and she will not loose control, especially on the highway? She is a careful but not a timid driver.
She should be fine. If it is the ABS module, the ABS will not work with the lights on.

Craig,

thank you kindly.

Boris

I stopped at an Autozone store. The diagnostics scan showed nothing (codes = 0). I assume its happened because the ABS+break lights were not on at that moment. They actually came on only once or twice yesterday while I was driving, each time for a few seconds.

The video instructions at http://modulemaster.com are very good indeed.

Thank you again for your help.

Boris

Sounds like one of the ABS senors has broken down if you have access to VAG this can be tested. Go into
brakes 03
Read measured value blocks 08
001
this will display the readouts of the ABS sensors for all four wheels, then just drive the car while monitoring the read outs and see if any are diffrent to the rest. If so the ABS sensor requires replacment.

Thank you crazyhawk.

I understand your reply but not the details. What is VAG? Please spell out. Whatever it is, I do not have it and cannot monitor the car while driving.

The big question: are you implying that I may have the ABS sensor malfunction IN ADDITION to the ABS ECU malfunction? Or is it possible that the ECU is fine? Based on what I read so far on this forum, I am ready to send the ECU for repair, but I will defer to your opinion.