A search did not find a clue to my type of problem.

For about a month now I've noticed my ABS INOP light will come on intermittently and stay on while the car is running. That is to say like every 4-5th time I start my car it comes on when the car is started. It stays on, but the next time I start my car it doesn't come on.

Thanks

 

Check your wheel speed sensors (2 in front, 1 in back if you don't have TCS, one on each wheel if you have TCS)

 

Odd as it may sound, also check that the center (high) brake lamps all work. In their infinite wisdom GM engineers decided to put that set of lights in the ABS circuitry.

 

The third brake light was my problem, or rather the ground at the end of that circuit had come loose.