Faulty ABS

[Mike_Buckham at ptk.pioneer.co.uk]

Hi all,

On my '89 200qta (UK car), my ABS light is permanently on and I can't find
any obvious reason for it. When I first switch on the ignition the
changeover relay in the actuator unit in the engine bay clicks on and off
rapidly twice, so there is some sort of control unit activity there. I have
checked the obvious things like the fuse and connections to the control
unit as per the Bentley manual (wheel sensor resistences, alternator
signal, ground and power supplies and a few others) but nothing reveals
itself to me. The first stage control relay (under the dash with the fuse
in it) is definitely on, but the control unit doesn't switch that
changeover relay on when the engine starts.

I have checked through the archives and found no help there. The Bentley
manual is no help when diagnosing the control unit itself, neither is the
SJM Auto-Technik site. Does anyone know how to diagnose the control unit
and perhaps get some fault codes from it? It is a Bosch control unit, but I
cannot identify which model it is. My car is too old to have a service port
to connect VAG-COM or similar to it. Failing that, can anyone suggest some
common faults that I can look for?

Thanks for any help.
Mike.

P.S. The previous owner had actually wired the ABS light to the alternator
charge warning light, so it looked like it was working properly. Sneaky,
eh?


This e-mail and any files transmitted with it are confidential and intended solely for the use of the individual to whom they are addressed.
If you have received this e-mail in error please notify your system manager.

Please note that any views or opinions presented in this e-mail are solely those of the author and do not necessarily represent those of the company.

Finally, the recipient should check this e-mail and any attachments for the presence of viruses. The company accepts no liability for any damage caused by any virus transmitted by this e-mail.