ABS/Trac lights on - suspect Wheel Bearing

[stan_5150]

A few days ago my ABS light and TRAC lights came on at the same time and by reading thru the forums I'm fairly convinced that it's a wheel bearing and/or sensor. (Which one is another story).

This started out as an intermittent event and I noticed that when the lights are illuminated then the car take a little more effort to steer, and when the lights are out, it seems like it's "normal" to drive. I did go through and check and refill my power steering fluid so that system is topped off with no dicernable leaks.

I'm wondering if anyone else has had the problem with the more difficult steering with the lights illuminated, or is it just in my head!!!

Thanks.

[richtazz]

As far as the ABS/Trac off, you are on the right track. Before changing a hub, inspect the wiring at all four corners, as the plugs can corrode and trip the light. You can also ohm test the hub bearing side of the connector, tehy should read 1k ohms. If you find one open or out of spec, there is the offending bearing. If nothing out of the ordinary is found, you'll have to have it scanned with an ABS capable scan tool (Advance and Auto Zone's free scan offer cannot pull ABS/Chassis codes) to find the offending hub.

As far as the lights on/harder to steer situation, check your serpentine belt and the tensioner for wear. Also, with the belt off, check the alternator bearings by free spinning it and listen/feel for a dragging/gritty sound. When you turn the lights on, the alternator turns to compensate for the increased electrical draw, and therefore imparts more drag on the belt. If the belt and/or tensioner are worn, this could cause the belt to slip resulting in harder steering.

[BNaylor]

Originally Posted by richtazz

As far as the lights on/harder to steer situation, check your serpentine belt and the tensioner for wear. Also, with the belt off, check the alternator bearings by free spinning it and listen/feel for a dragging/gritty sound. When you turn the lights on, the alternator turns to compensate for the increased electrical draw, and therefore imparts more drag on the belt. If the belt and/or tensioner are worn, this could cause the belt to slip resulting in harder steering.

I thought he was referring to getting the problem when the ABS and Trac Off light came on and not the car's lighting system? Or did I miss something.

That is a weird one. I have never heard of that one.

Well, it looks like it is hub time.

[richtazz]

I just re-read it and I think you're right Bob (look at the time of my reply, I didn't have a whole cup of coffee in me yet, ) . I mis-read it as it steers hard when the vehicle's headlights are on. My guess is if it steers harder when the ABS/Trac-off lights are on, one of the front Hub bearings is binding, creating more rolling resistance, hence the harder steering.

[BNaylor]

Originally Posted by richtazz

I just re-read it and I think you're right Bob (look at the time of my reply, I didn't have a whole cup of coffee in me yet, ) . I mis-read it as it steers hard when the vehicle's headlights are on. My guess is if it steers harder when the ABS/Trac-off lights are on, one of the front Hub bearings is binding, creating more rolling resistance, hence the harder steering.

Yeah, I was not sure. But I know what you mean by that first cup of coffee early in the morning. I'm worthless without mine.

The part I hate about bad hub bearings is the noise. It is normally at an audible frequency that is annoying. I ran 2 weeks with a bad hub bearing on the front end until the part came in and I had time to replace it. The noise was so deceptive I replaced the wrong side.....lol.

Now the ones with ABS and Trac off popping up are easier to troubleshoot and test. When in doubt do both of them.

[richtazz]

Yep, driveline noises can transmit from side to side (or front to back on a RWD vehicle) and be very difficult to narrow down. Unless you are part of some stunt driving team and ride around on two wheels, hubs get the same mileage, and if one has worn out, the other isn't far behind. If you can afford it, replace both while you have it apart so you don't have to get the tools out and get dirty a second time.

[mrbertnoternie]

Actually when my abs/low trac light came on the speed senstive steering part also is out for some reason, not sure how they are interconnected. I did replace both my front hubs and that stopped the humming but still havent got the abs/trac light to go back off and regain that part of the speed sensitive steering, which for those that are not familiar with it provides easier turning of the wheel up to about 20 miles and hr.

[BNaylor]

Originally Posted by mrbertnoternie

Actually when my abs/low trac light came on the speed senstive steering part also is out for some reason, not sure how they are interconnected. I did replace both my front hubs and that stopped the humming but still havent got the abs/trac light to go back off and regain that part of the speed sensitive steering, which for those that are not familiar with it provides easier turning of the wheel up to about 20 miles and hr.

What year is your Grand Prix and model? Then you must have the variable effort steering system instead of the regular rack and pinion.

Then that is normal because the wheel speed sensor provides a reference signal to the control module for that system through the Electronic Brake Control Module (EBCM). Confirmed with GM GP service manual.

BTW - The EBCM also controls the Steering Gear MSVP Actuator so it controls the variable steering.

The variable effort steering system is an option so not all Grand Prixs will have it.