ABS Issues

[carsub]

I have an annoying problem with my ABS in my 1992 Legacy BF GT. The dash warning light comes on after the first few times you brake and stays on. I have tested the ABS and it doesn\'t seem to be working as the wheels lock up under heavy braking.

Firstly I tried cleaning all the sensors and it made no difference, then I replaced all them with another set and still no difference. I then looked on the forum and found out about the light on the ecu and the fault codes etc. It was saying there is a fault with the R/R sensor which I have since checked and changed it again and this time I also checked and cleaned the hub ring and the ecu is still saying the same thing.

Can anyone help with what might be at fault, would it be the ecu or the main control unit in the engine bay?

[Rosssub]

Maybe loose/worn wheel bearing on the R/R?

Causing the disc/rotor to wobble slightly, so the sensors pickup can\'t read that wheel spinning, (or the ABS module thinks the R/R wheel has locked up).

Edit: In wiring diagrams it looks like the wheel sensor itself might earth to the hub? Make sure the sensor and where it attaches are both clean (sensor earth).

[carsub]

I have checked the wheel bearing and it appears to be nice and tight. I also checked both serfaces (hub and sensor) for dirt and they both looked good. Yesterday I tried replacing the ABC ECU and it made no difference, could it be the main unit under the bonnet that is causing all the trouble?

[tebbyj]

Have you cleared the code? some systems are hesitant to clear codes, they have to be manually cleared especially when it comes to ABS/SRS stuff. Leave the NEG battery terminal off for 15mins is the easiest way.

Another thing is check the wiring back to the ABS unit, you may have a brake or a dirty connector causing a false signal.

[carsub]

I cleared the fault and it has made no difference ???

[Rosssub]

What fault code are you getting, 25? 26?