The ABS is not activated during normal braking. So your problem may not be the ABS. Pulsing can be caused by other things as well, like warped/heat glazed rotors, sticking guide pins etc. Also, corrosion and internal muck build up from infrequent brake fluid changes can cause pistons and valves to stick. My rule is don't overlook the obvious.
Of course your system could be getting erroneous signals.... VW added the self-diagnosis and fault memory in '89 or '90 (check the Bentley for the starting VIN). If you have this feature, a VAG-COM or the VAG1551 would save you some aggravation. Don't know if you can blink out ABS codes or not. If not, Bentley covers in detail some simple functional tests for every ABS system component except the control unit. All you need is the Bentley, an Ohm meter and some coffee or beer, depending on what time in the morning you get started. =) Shouldn't take long to bust it out Don't forget to check the toothed rotors, which rotates through the wheel speed sensors' magnetic field which generates the signal to the control unit. I have heard of these getting damaged. We have ABS on the wife's 1991 200 20V and have yet to have any problems. On that car, the ABS is absolutely transparent unless a wheel begins to lock while braking....only then will the brakes pulse as the system reduces hydraulic pressure from the affected wheel. Steve Hauptmann South Carolina -----Original Message----- From: Adam Frank [mailto:[email protected]] Sent: Tuesday, October 19, 2004 7:07 PM To: [email protected] Subject: Re: [a2-16v-list] New 2.0T 16V " I remember when people were up in arms about ABS. They were so worried about a computer thinking for them. Well, think about how much safer we are in typical panic stops in the rain etc, than without ABS. Now we even have brake assist, traction control, stability control.....margins for safety. " The ABS on my GLI has been flogged with problems for years. once driving the car long enough to warm up the brakes, the ABS light comes on and stays on till i shut the car off. Any time i step on the brakes firmly after that light is on, the brakes 'pulse' as i slow down instead of allowing a smooth decline in speed.. Now i know this is partially ABS's job to do so. But not all the time everywhere i go. Same problem happened on my mom's '00 Hyundai; brakes pulse when she slows down. My GLi shows first hand what a computer thinking for me can do, malfunction.... Maybe im too old fashioned. By the way, anyone know of this problem? The ABS system seems to have a 'brain' mounted in the trunk on the side. anyone else have their ABS light come on for no reason? Ive checked myself and had the sensors checked. They seem to be in place and nothing is out of the ordinary.. _______________________________________________ a2-16v-list mailing list [email protected] http://mail.a2-16v.com/mailman/listinfo/a2-16v-list For list archives, see listinfo link above.
