FYI: Odd ABS/TCS Issue

[pajeff02]

A couple of months ago, while leaving our driveway to head into the office, the dash on my '10 Cadillac CTS 4 lit up with ABS, Traction Control, and AWD warning messages. Later that day, I borrowed the brake code scanner at our local Autozone and it read a sensor issue with the left front wheel. When I put the car up on the lift, everything appeared to be intact and tracing the wires along the underbody I could not find any evidence of damage or corrosion. I was about convinced that I simply had a bad sensor when I noticed something odd looking on the back of the wheel bearing.

Rather than a dedicated sensor ring with teeth (that we are all accustomed to seeing) there appeared to be a thin flat magnetic ring attached to the back of the wheel bearing. What caught my attention was that this ring had a large chunk missing. Using my air compressor, I blew away some of the dirt and grime for a better look and a small piece of the ring fell away. Replacing the wheel bearing solved the problem as the ABS/TCS system reset itself within about 1/8th mile of our house on the test drive. What really vexed me was that this missing chunk also completely disabled the AWD system leaving me with a rear wheel drive car after a fairly significant snowfall. Just one to keep in mind if you get a warning light on a newer GM vehicle. I have no idea how many models utilize this style sensor ring.

[SMWS6TA]

And I'm sure it costs just penny's to fix it too.


I found out something with my Durango when I went with new tires. My fornt set had belts showing and was between payday's so I ordered just 2. But these were a bigger size then what I've been running. So I put the new one's on the rear till payday. I then learn that the ABS sensor is also tied to the speedometer. When it tripped it killed the speedometer gauge while in motion. It dropped to zero. WTF, who ties those 2 together?

So once I got the last 2 tires no more issues with ABS.

[pajeff02]

Agree. Both of our results are dumb for this day and age. I absolutely understand that the ABS and Traction Control can not work without reading wheel speed, but to kill the AWD rather than default it to a specific setting was quite a shock.