944S2cab
Member
My car is a 1995 SL500 with ASR. After driving for about 10 miles the ABS light comes on and stays on. A few minutes prior to it coming on I felt a single slight kick from the pedal while braking gently.
Using a home-made blink code reader has given me fault code no. 8 i.e. solenoid valve, rear axle. I cleared the code and took the car for a run and the same thing happened. The ASR light has not come on.
I have checked the multi plug connection at the ABS unit under the bonnet; it is clean and tight. I have cleaned the earth connection for the ABS unit. I have checked and cleaned the 4 x 10 amp fuses in the box in front of the windscreen which contains ECU's and the 38 pin diagnostic connector.
Under the car I have checked the outputs and internal resistance of the 2 rear wheel speed sensors. Spinning each road wheel one turn in a second produces an average of 0.3 - 0.4 Volts AC. The resistance of each is 1.6 KV. I assume that the rear wheel sensors are sending a correct signal to the ABS unit.
I tried to get into the ABS unit in situ without disturbing the hydraulic system. I removed 4 screws holding the black plastic plate, and I removed a plastic cover lower down. This revealed 2 relays. I could not work out how to separate the black plastic plate from the hydraulic part of the ABS unit. At this point I gave up as I was out of my depth. I have never dismantled an ABS unit.
If anyone can suggest any further checks it would be appreciated.
Using a home-made blink code reader has given me fault code no. 8 i.e. solenoid valve, rear axle. I cleared the code and took the car for a run and the same thing happened. The ASR light has not come on.
I have checked the multi plug connection at the ABS unit under the bonnet; it is clean and tight. I have cleaned the earth connection for the ABS unit. I have checked and cleaned the 4 x 10 amp fuses in the box in front of the windscreen which contains ECU's and the 38 pin diagnostic connector.
Under the car I have checked the outputs and internal resistance of the 2 rear wheel speed sensors. Spinning each road wheel one turn in a second produces an average of 0.3 - 0.4 Volts AC. The resistance of each is 1.6 KV. I assume that the rear wheel sensors are sending a correct signal to the ABS unit.
I tried to get into the ABS unit in situ without disturbing the hydraulic system. I removed 4 screws holding the black plastic plate, and I removed a plastic cover lower down. This revealed 2 relays. I could not work out how to separate the black plastic plate from the hydraulic part of the ABS unit. At this point I gave up as I was out of my depth. I have never dismantled an ABS unit.
If anyone can suggest any further checks it would be appreciated.
