ABS Problem [Archive] - GrandAmGT.com Forum

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pushnfords
01-14-2006, 12:49 PM
My wife has a '94 Grand Am GT. I redid the front brakes a few months ago: new rotors, calipers, pads, and hub bearings. The brakes have been working great until two days ago. We were out shopping and it started to rain...at the first stop sign we came to it was acting like the ABS was activated although we were only going 25-30. I thought we might have just been sliding on some slick painted portion of the parking lot...until it did it again. Yesterday the brakes were doing the same thing on dry pavement and I could hear a clicking coming from the engine compartment.

I'm a mechanic but was trained in restoration and pre 1980 vehicles so I've never messed with ABS. What do I need to look for? Maybe a bad wheel sensor? Or is there part of the ABS by the master cylinder that could be causing this? How do I test these components?

Thanks,

Derek

eaglesrealm
01-26-2006, 07:51 PM
I'm assuming it's not throwing a code? The ABS will only cycle like that if it thinks (true or not) that you are in a slip condition of some sort. I would guess that you have an intermittent wheel speed sensor, which will be a pain to track down.

Does it always happen when it is raining? Could be moisture getting into the connectors?

Basically, basic ABS is useless without it's speed sensors. Those are the "eyes and ears" of the system. There is a remote chance that something is malfunctioning in the ABS control module, but I highly doubt it.

FYI - I am sure you know this, but all ABS systems are built such that power loss, or component failure SHOULD lead to just base brake push through. So you should not be in risk of losing your base brakes because of this. But it is annoying when it goes off if you don't want it to. And even more annoying if you need it to go off and you have this intermittent malfunction. :)