ABS Question

[philippe]

Hi There,

My car is an A3 '97 1.8 20V non turbo. I'm having troubles with my ABS system. When starting the car, the ABS light on and when started, it falles off which normally means that the ABS system check was succesfully. But I drive away, the ABS light turns on at 20 KM/H. First i thought that one of the wheel sensors were dirty, so took the wheels off and cleaned them all but with no succes Then I thought let's go to a dealer and have a system check. Result: 01276 Hydraulic pump - signal out of tolerance. They could not tell me exactly what the problem is and they needed almost a day of work to find out. I think most of you guys know that it won't be a cheap job at audi's. Then i started some own research. Because i was still thinking about those damn sensors ( especially the rear sensors i did the next: Because someone told me that the ABS system activates above 20 KM/H I did this: started the engine, made small burnout the KM metre raised till 60KM/H but the ABS light stayed off (did this while it was raining, my 1.8 can't make a burnout to 60KM/H on a dry street ) Then when i normally drove away, the ABS light turned on at 20 KM/H

Can someone please tell me what the problem is? And Does ABS activates when all wheels are rotating at 20 KM/H or only when the front wheels are at 20 KM/H?

[A3Floyd]

I cant really help you much with your question but the one thing that i have found out is that the ABS pumps are a known weakness on the A3's. My quess is that the system may not be able to complete the full ABS system check with just the 2 front wheels rotating, hence, no error when wheelspinning. The system should only be able to return an error code once all four sensors have been checked unless an error is detected in the sensor itself. Not sure if this is correct but thats how i'd program it. I'm having similar problems with my A3 and trying my best to get around the £1000 repair bill!