I have a 2008 Lucerne. I replaced the rear passenger bearing/hub with a MOOG bearing last year because of noise/wobble/etc. Recently, my ABS light came on as well as the "Service Brake Assist/Service Traction Control/Service Stabilitrack" messages. The code reader showed codes C0050-00 (Right Rear Wheel Speed Sensor Circuit) and C0050-0F (Right Rear Wheel Speed Sensor Circuit Erratic). I replaced the bearing again, and the light/messages continued. At first it was very intermittent, would come and go as I was driving. I don't know that it is specific to hitting bumps, as it will come and go as I'm sitting at a red light not doing anything. I checked as much of the wiring as I could trace from the wheel under the car (it goes into a bundle with other wires, so I don't know where it goes from there).I went to the auto parts store and borrowed another hub which I plugged into the harness. I then cleared the codes, and it immediately set the codes. I then replaced the harness connector, and still I have not solved the problem. The ABS light/messages are on pretty much the whole time now (they do turn off briefly from time to time) .Does anyone know what else I can check? Thank you in advance!

You need to use a meter and load test the circuit.

Have you noticed any difference in braking performance since this started happening?

Help me out.. I have a meter. How do I load test the circuit?

I have not noticed any differences in braking. Everything feels normal, but I haven't had the opportunity for the ABS to kick in (fortunately!!)

I agree with carfixer007 ^^^^^^^

Load test it.

If it is a completely bad circuit, you might be able to find that out with a simple continuity test.

I suppose you could have a bad series of replacement hubs, so if you have a meter that will show performance of the hub circuit, you could figure that out.

Youtube search of 'Load testing a circuit'.