Brake Antilock Wheel Speed Sensor problems of the 2004 Chevrolet Impala

Frequently, the abs activates the brakes while in motion and no pressure is placed on the brake pedal. Usually the abs light and traction control turn on afterwards and indicate they are now disabled. Sometimes the lights turn on when the engine is started. The dealer said the speed sensor was defective, so they were replaced twice, but this did not fix the problem. This portable had been ongoing for over 6 months.

I have been experiencing a traction control problem. When I make sharp turns the service traction system light comes on, after this light comes on it pulls to the right and makes it hard to stop and even slides sometimes. I have replaced all speed sensors and replaced the wires and the problem is still reoccuring.

For several months now, more often when slippery winter conditions exist but this can happen even on perfectly dry road conditions. When I back out of my driveway and put my Impala into drive and start to accelerate the dashboard warning light for traction control and abs braking systems. This happens with a noticably loud grinding noise in the front end. Automatically I release the accelerator and the systems half the time seems to reset itself as the grinding noise stops, the traction control light goes out and the abs warning light goes out as well. I begin to accelerate with no problem at that point. The other half of the time the lights all stay on for the length of my drive, with the grinding subsiding when I release the accelerator. I took the car to a Chevrolet dealer, explained the situation and they told me it may be a speed sensor going bad. They would have to diganoise it and possibily replace the sensor and quite a large cost. I argued that if my brakes are not working properly than this may well be a safety issue and Chevrolet should repair the problem for free. No chance. I took my car to another dealer with the same result. Pay for the repair.