battlewagon
Full Access Member
Recently picked up a 46k mile 4WD 2008 Tahoe LS. Had the usual TC/ABS/Service Stabilitrak error when I bought it. Using my non-factory scanner, the DTC was for the rear left wheel speed sensor. Purchased a cheapo brand sensor with harness from Rock Auto. Upon replacement, the following occurred:
The lights were gone, but almost immediately (pulling out of driveway and applying brakes at less than 10MPH), ABS was kicking in the pedal. A few moments later, all the lights come back on. Clear DTC and codes, and ABS starts kicking again at low speed. It kicks whether braking in a dead straight line or braking while turning <10MPH or on the road. Lights come back on. Clear, ABS kicking, but this time light doesnt come on for about 20 miles. When it came back on again, I cleared, same symptoms (ABS kick), but light has not returned for many miles and days.
All of the above examples, the live data shows the rear left sensor displaying the proper speed output when driving; matches other wheels when driving in a straight line, adjusts accordingly in turns, etc. This proper wheel speed output happens no matter what, whether the TC/ABS lights are on or they aren't. Pulled the sensor back out today, had some wet black fluid on it, looked like used motor oil. So maybe the axle seal is going, but that hasn't affected the sensor magnet's operation, as evidenced by the correct data output.
So my question is this: if the wheel speed sensor is outputting the correct data consistently, and the ABS pedal is still kicking in the pedal when breaking, the issue must be in the ABS system, such as the module, computer, etc, right?
I haven't really heard of modern GM trucks having bad ABS modules/computers, whereas the wheel speed sensors are known pieces of junk, but replacing the sensors almost always fixes the issue.
Thanks all in advance.
The lights were gone, but almost immediately (pulling out of driveway and applying brakes at less than 10MPH), ABS was kicking in the pedal. A few moments later, all the lights come back on. Clear DTC and codes, and ABS starts kicking again at low speed. It kicks whether braking in a dead straight line or braking while turning <10MPH or on the road. Lights come back on. Clear, ABS kicking, but this time light doesnt come on for about 20 miles. When it came back on again, I cleared, same symptoms (ABS kick), but light has not returned for many miles and days.
All of the above examples, the live data shows the rear left sensor displaying the proper speed output when driving; matches other wheels when driving in a straight line, adjusts accordingly in turns, etc. This proper wheel speed output happens no matter what, whether the TC/ABS lights are on or they aren't. Pulled the sensor back out today, had some wet black fluid on it, looked like used motor oil. So maybe the axle seal is going, but that hasn't affected the sensor magnet's operation, as evidenced by the correct data output.
So my question is this: if the wheel speed sensor is outputting the correct data consistently, and the ABS pedal is still kicking in the pedal when breaking, the issue must be in the ABS system, such as the module, computer, etc, right?
I haven't really heard of modern GM trucks having bad ABS modules/computers, whereas the wheel speed sensors are known pieces of junk, but replacing the sensors almost always fixes the issue.
Thanks all in advance.
