I have a 1996 Cadillac Eldorado and somtimes my ABC/Traction Control lights go on. Sometimes when I restart the car they are out.Then after that they go on again. My breaks seem to working just fine. However, occaionaly I feel a roughness or virbration in the pedal. The ABS/Traction Control light does not come on for a while after that. I checked the break pads and all the connections at the wheel sensors for loose connections and corrosion ,but all is fine.The Chiltions General Motors manual for my car says, I have a Bosch system.I don’t have a code reader for ABS. However,it says that if I put a jumper wire between the A and H therminals, or ground the H theminal at the ALDL, I will be able to read the codes stored buy counting the flash sequance, except if the current or hard faults involve the solenoid valves or pump motor. If one or more of the codes is/are Code 41, 45, 55, or 63, diagonostic display of the trouble codes cannot be occor until the fault has been repaired ( use of the scan tool eleminates this problem; all stored codes will display ) The problem is, one, there is no pin in the H terminal, it’s blank, And two I do not have a scan tool. So, I’M stuck. Can you unstuck me? Should I take a chance and replace the pump motor and solenoid valves and nickle and dime myself to death. Is there a kit available for the solenoid valves?
Many auto parts stores like Advanced Auto Parts and Autozone will read the codes for free. You might want to give them a try.
BTW good job on doing your research and testing.
You might want to do something as simple as checking the tone rings for the wheel speed sensors for the ABS. Because the ABS and the Traction Control System work hand and hand. If the ABS light comes on, the TCS light comes on. And vice-versa.
If there’s a lot of debris in the tone rings for the wheel speed sensors from the brake dust from semi-metalic brakes, it can srew up the signal for the wheel speed sensors. This can cause the ABS light to come on which in turn causes the TCS light to come on.
So, get a can of sensor safe brake cleaner, remove the front wheels, and blast both wheel speed sensor tone rings with the brake cleaner, and see if this turns the lights off.
As has been said, get the codes read by someone. I’ll bet you dollars to doughnuts that it’s wheel speed sensor. I say that because it’s always a wheel speed sensor. And since the traction control and ABS both take input from those sensors… well, there you go. I like Tester’s idea of cleaning the tone rings. That may-well take care of your problem.