This problem has been getting worse over the months. It started with my ABS kicking in when it didn't need to -I'd hit the same pothole once in awhile while braking and I could feel it working with the brake pedal. I've moved since and so don't hit that pothole anymore, but now it kicks in whenever I'm braking more than slightly and turning right at the same time. Then I'm getting the ABS and sometimes the trac off and check engine lights. I'm checking my fluid level today, but if that's not it, what can it be?

The traction control depends on information from the ABS system, so if the sensors are giving faulty readings and set an ABS code, the Traction system will automatically shut off. This vehicle is know for having bad wiring at the right front wheel.

I wrote an article about this system here:

ABS and TCS on GM vehicles--ABS light on TCS off

First, have the codes read to confirm that it's the right front wheel speed sensor. It usually is.

If you want to do the diagnostics yourself, unclip the ABS sensor at the right front wheel. Then unclip the main connector at the EBCM (electronic brake control module) behind the plastic covers on the driver's side under the car. You'll need to check for continuity on the wiring harness from the sensor to the main connector. Use a Digital volt ohm meter and connect the leads to each end of a wire (do it one wire at a time). Then wiggle the wire along the route to find the break. It's usually about 6" from the ABS sensor.

If you don't find a break, then the problem is either in the ABS connector or the wiring to the wheel bearing. In my latest repair, the wiring had literally been ripped out of the wheel bearing. The good news is that the wheel bearing/ABS sensor is fairly inexpensive and kind of easy to replace. I bought the replacement wheel bearing )Timken brand) from RockAuto for $87.

Remove the old axle nut and toss it. Then remove the three bolts holding the wheel bearing to the steering knuckle. The axle isn't exactly pressed into the bearing, but it is a tight fit. So you might need a puller to get it out. Or, place the axle nut back on the threaded portion and use a heavy plastic mallet to push the splined axle shaft out of the bearing. Then swap out the bearing, paying attention to the location of the wire connector (it should be at the top).

Re-install the 3 bolts, but coat them with thread locker first. Then install the axle nut. You WILL need a torque wrench for that. Torque the new nut to 175 lbs or whatever is shown on the instruction sheet.

If you find a broken wire, you can either try to replace it or buy a new harness.

I too have a 2001 Buick Century Custom with 25000 miles. All three lights, Trac, ABS and Service Engine light were coming on after driving 40-45 minutes and would stay on. I took it to the OEM garage and was told it would cost $600 for a NEW wheel bearing/speed sensor. I replaced this on my own for $70 from a local parts store with same result. Finally took it to another shop and they replaced the same wheel bearing/speed sensor again with the same result. Next they replace the wiring harness and once again lights on. Finally, the ordered a NEW ABS control module and guess what, problem solved. I hope this helps someone with the same issues we had.

It is unfortunate that all too many supposed "authorized" dealers and mechanics just throw parts at something because that is what the "book" says to do. My son is a mechanic who works exclusively on large displacement diesel engines in Tractor Trailers. They have more electronic controls that cars do today and what may seem as a simple control module can cost in the thousands. No one can afford to throw parts in and not solve a problem. I have been an electrical systems trouble shooter for most of my life and have saved him literally hundreds of thousands of dollars by teaching him correct trouble shooting procedures. People tend to overlook the obvious. In this case, a system or system was not working. The first place to look is the part that runs and controls the system... not some peripheral part of the system.