Brief ABS activation in the am..

[kevindanielk]

The first time I step on the brake pedal, after I start to move my 95Q, in the morning, the abs system briefly pulses for a second. This happens every morning, but not at all for the rest of the day, even if I stop and restart the car and start moving again. Must have something to do with sitting overnight. I have no warning lights on my dash and the abs light doesn't even flash for a second, when it does the pulse thing in the morning. My car does not have traction control and this has been happening since earlier this year, around spring time. My abs system currently works fine; it just bugs me to know what might be causing it so I can put a stop to it.
On a side note, I did have a Jeep cherokee that did the same exact thing, for years, with no ill effects. I just never got around to fixing it.
I'd appreciate any thoughts or ideas as to what might be causing this, only after sitting overnight?

[Infinitiguy19]

Perform the self diagnostic shown in the service manual in the Brake (BR) section. Do it on a closed road so no one complains about you going 19 MPH.

[goody90q45]

The first time I step on the brake pedal, after....... in the morning, the abs system briefly pulses for a second. This happens every morning, but not at all for the rest of the day, even if I stop and restart the car and start moving again........

My 94Q used to do the same thing and only in the morning. I could feel the brake pedal slip (pulse) about 1/2". This topic came up a few years ago and the answer was that this was a programmed self-check. If it didn't pass the ABS light would come on. I was happy with that answer since I never had any ABS issues either. It still doesn't explain why I never felt the pulse except in the morning backing up out of my sloped driveway. If it is a self-check I should feel the same thing after the Q's been sitting at work for 9 hours.

[Infinitiguy19]

I read what he typed wrong because I thought he said the ABS light comes on for a second.

Please ignore my first post.

[kevindanielk]

I'm glad and can accept the fact that it's only going through a self-check. Strange that it only does it after sitting overnight. Maybe it's a 'condensation on the wheel sensor' thing that only sets it off in the am. Happens usually while I'm coming out my driveway, foward or reverse. As long as all remains well with the abs system, I'm sure I can live with it.

[Q451990]

It should do it every time you drive the car, but it's always more noticeable in the morning for some reason. You will notice it more when it's cool or cold outside, and when you're on an incline. I had a house with a fairly steep driveway once, and it felt like I was backing over a small limb in the driveway every time I pulled out.

Heath

[kevindanielk]

So, the owner's manual states that the abs system does indeed perform a self test, when the vehicle speed reaches 4mph, everytime the abs system is reset. It is definitely more noticable in the am so I guess that's why we only notice it then. Ok, all's good with my Q then, for now. Thanks for the input everyone.