1997 ABS System activating unexpectedly

1997 Skylark 2.4L, 193k miles

My daughter asked me look at her car because the brakes "sound funny".
So I drove it and putting light pressure on the brake pedal caused it to act normal. However when putting moderate to heavy pressure on the pedal the ABS system is activating and the wheels are still rolling. I'm quite sure the wheels were not skidding as it was on dry pavement and I wasn't applying enough pressure to cause that.

So I started driving the car to work today so I could monitor the brakes and from what I noticed so far, this behavior isn't constant. I applied some heavy braking this morning and the ABS didn't activate, just normal braking.

I'm defining the "ABS system activating" as what the brakes would normally do when braking on ice.

Does anyone have any suggestions of where I should start diagnosing this problem.

Thanks, Dave

I had a problem where the ABS light would stay on for no apparant reason. This was an intermittant problem and it finally turned out to be due to a faulty ignition switch. Maybe you could start with an electrical check.

1997 Skylark 2.4L, 193k miles

My daughter asked me look at her car because the brakes "sound funny".
So I drove it and putting light pressure on the brake pedal caused it to act normal. However when putting moderate to heavy pressure on the pedal the ABS system is activating and the wheels are still rolling. I'm quite sure the wheels were not skidding as it was on dry pavement and I wasn't applying enough pressure to cause that.

So I started driving the car to work today so I could monitor the brakes and from what I noticed so far, this behavior isn't constant. I applied some heavy braking this morning and the ABS didn't activate, just normal braking.

I'm defining the "ABS system activating" as what the brakes would normally do when braking on ice.

Does anyone have any suggestions of where I should start diagnosing this problem.

Thanks, Dave

Thanks for the reply Tom. You may not be far off with your suggestion. I drove this car to work every day for a week and it wouldn't repeat the symptoms so I'll have to wait for it to show up again.

I really can't complain about this car, I bought it with less than 10K miles on it and it has been virtually bulletproof the entire time I've had it. The only thing I've spent money on outside of the norm is the a/c unit. I changed the spark plugs the first time when it had 163k on it. It had plenty of power and the fuel economy was as good as it ever was, but I thought surely plugs can't last forever. They didn't look bad at all, although the gap was a little wide.

Dave