Ooooh. Once the light comes on there should be at least one diagnostic fault code stored in the ABS computer. It's important to not disconnect the battery or let it run dead until those codes have been read and recorded or that valuable information will be lost.
Don't worry about the Traction Control light. That one will turn on because the system makes use of the ABS system. When the ABS computer detects a problem, it turns the light on and disables the system. You already figured out that the ignition switch must be cycled off and back on to reset the system.
The good news is the light does turn off at times. That would tend to point to an electrical wire / corroded connector pin / sensor problem vs. Something in the hydraulic controller. If the light turns on right after shifting out of "park", the computer detected a problem during its self test that it does for a few seconds. If the light turns on randomly after driving a few hundred feet to a mile or so, check for cracked toothed tone rings by each wheel. The crack is detected as an extra pulse per tire revolution, but the computer will see the other three tires going the same speed so it knows you're not going around a sweeping curve, plus, it knows you wouldn't be doing that for up to a mile. GM has also been having a huge problem with front wheel bearings on front-wheel-drive cars. The bearings are not defective but they develop enough play to cause the built-in sensors' signals to drop out. This usually happens within 20,000 miles but I'm pretty sure it applies to newer model cars.
Friday, October 22nd, 2010 AT 11:55 PM