Hi,

I recently purchased my first Audi, an 1998 Audi A4 2.8L Quattro, and a few days later the abs light and break light came on. I have a feeling its because i left the eBrake engaged and drove for maybe 30 seconds. The light(s) are not always on but usually come on 10-20 minutes after driving(The ABS light and the Break light), the ABS light is solid and the Brake light is flashing. The lights sometimes turn off, then come back on a few minutes later. This had not happened previous to leaving the eBrake on for that brief period while driving.

I have read a few similar posts to try and get a better understanding of what I will be needing to do to get this fixed. I read that it could be a dirty sensor or the modulator could be going out, but on all these posts it seemed like there was a noticeable effect on the question askers breaks or ABS. In my case the light just comes on sometimes and also stays on sometimes, but does not seem to effect my driving at all. I tried to use my code reader device(Innova 3100 ABS) to diagnose this problem, but when I pressed the "ABS" button on the face of the device it did not have Audi listed under the makes, so i did not continue trying to figure this out through the reader.

When I plugged in the code reader device(INNOVA 3100 ABS) into the car and I got 3 codes back. These codes do not seems to relate to the problem I'm having with the ABS and Break light, also my check engine light is not on. Could these be codes that previously went off and are still saved on the reader. I have read some other posts and know that these Misfires could be because I need to replace the spark plugs or coil packs.

1) P0300 - Random Misfire Detected
2) P0304 - Cylinder 4 Misfire Detected
3) P0305 - Cylinder 5 Misfire Detected

I am going make an appt to get the car checked out at a dealer and maybe do a complete inspection to see what else could be wrong, i'm curious if anyone has any idea what my problems could be and if there are any simple test/solutions I could try before getting it over to the dealer.

One thing i would like to try is to tap the brake calipers with a hammer or something to try and get ride of any dust on there. I'm wondering if this can be done with the car completely together(Ie, wheels on)?

Any help or input would be appreciated. I also attached some pictures of the code errors I got when I used the code reader to try and help diagnose the problem.

First post, please be gentle with me, I will take any constructive criticism in a positive light.

Thanks

Justin B

 

This ABS issue is one that will be nearly impossible to diagnose without the right tool; in this case the right tool is VAG-COM or VCDS, which is the specific Audi/VW scan tool.

You'll need the ABS/brake lights on/flashing for proper diagnosis (this means for you, don't turn off the engine).
Once you enter the ABS module, you can view fault code(s). This should point to a specific wheel speed sensor as the issue, then you can verify one of the following issues:
1) wheel speed sensor tone ring is damaged or broken
2) wheel speed sensor is not pushed in far enough and therefore not properly reading the tone ring
3) wheel speed sensor is damaged/broken

There is also the possibility that your ABS module is going bad. This can be verified while the ABS and brake lights are on/flashing, and you try to connect to the ABS module, but VAG-COM/VCDS report that it cannot communicate with the module.

 

Just wondering, would a blue driver work for this?

 

I'm assuming you mean the generic blue VAG-COM cable? I think it should, but I'm unfamiliar with that and the associated VCDS Lite software.

 

Actually i guess its a Lemur Monitor... ? Here is the link, just so you know what I was talking about.

Lemur Monitors - BlueDriver - OBD2 Bluetooth Scan Tool for Apple and Android Smartphones and Tablets

I went out and tapped on all my calipers with a hammer and the lights have gone away and have not come back.... so far.... I did far more driving than what it usually takes for the lights to come on, I also tested to make sure I could feel the ABS working and I believe it was. So perhaps they were just some dirty sensors!!!!

Either way I really appreciate the help MetalMan, and if the problem comes back in the future i'm glad I have your advice to reference when needed.

I only regret not trying that out before asking the question, so as not to waste your time.

Thanks so much again!