Bad Sensor?

Hey,

I have a 02 Pontiac Grand Prix GT with about 65,000 miles on it. I recently noticed one day after work when i started my car that the ABS light on the dash was on and the Trac OFF light was also on. I turned off my car and restarted it, but this time they were both off.

The 2 lights seem to come on when i start my car. Or if they off when i start my car, they will come on when i perform a normal stop. The steering wheel also becomes harder to turn for some reason. It is a noticable difference in the steering wheel.

The brakes seem to working fine. I think it could just be a bad sensor or maybe a bad fuse or something like that.

If anyone could help me out that would be great, thanks!

It sounds as if you have a bad ABS wheel speed sensor (which is part of your hub bearing assembly) or a problem in the wiring to it. If your car has the magnasteer variable effort steering system, it uses the signal from the wheel speed sensor to determine steering effort (that 's why your steering gets harder when the lights come on).

If it is a bad sensor do i need to get a whole new wheel hub assembly, or just a new sensor?

The speed sensor and wheel hub are one unit and therefore has to be replaced as such. You can have your car scanned by a ABS capable scan tool to isolate which hub/speed sensor is bad.

will a store such as auto zone be able to perform the scan for me? Will this cause any harm to the car if i keep driving without getting it fixed?

Autozone cannot diagnose your ABS code however, I believe they do sell the ABS scan tool. You can find either a GM dealership or a reputable brake/muffler shop in your area that can scan your ABS code. Where I live a local brake/muffler shop scanned my ABS system for free. You can call around in your area and find a shop that can do the scan.

I got the same problem on my 2004 pont grand prix gtp 80k miles. Let me know how you fix it.

I got the same problem on my 2004 pont grand prix gtp 80k miles. Let me know how you fix it.

You have to get the car scanned in order to find out which HUB assy is bad. The scanner must be capable of scanning for the ABS dtc codes.

I agree but a GM Tech II scan tool which means a trip to the dealership. The generic ABS scan tools are too expensive for the average owner and do not translate or convert DTCs for a GM/Bosch ABS system properly which start with C1XXX.

This doesn't sound like a bad ABS wheel sensor since it is failing ABS initialization at start up. The wheel sensors are not tested until the car is moving and the speed is greater than 8 mph. :2cents:

You can test a wheel sensor with a digital multimeter to rule it out.

The stiff steering is because the EBTCM module controls the Magnasteer steering.