Topic

I have issues with the ABS system on my car, than  I could really do with Pscan showing me what is wrong. The car system is a Bosch 5.3 and when the interface failed on the original, I purchased a known good ECU and replaced with that. That behaves in the same way. I have confirmed the link wire from the OBD connector to the ECU harness plug is good as is the component earths, so I am at a loss to understand why there is no communication. Any help or guidance would be appreciated

What is the car?

I was about to ask the same.

Any 25/45 or MGF (with ABS) should work with the ABS5.3 protocol.

Maybe find someone else locally who has another car and try it pscan on theirs?

Have you checked that the ABS module is receiving power?

I was about to ask the same.

Any 25/45 or MGF (with ABS) should work with the ABS5.3 protocol.

Maybe find someone else locally who has another car and try it pscan on theirs?

Have you checked that the ABS module is receiving power?
 

Its a Rover 200 BRM that has the same modulator/ecu as the MGF and uses 5.3 protocol. Haven't physically checked the fused 12v supply, but on the basis that the ABS warning light is on permanently, I had assumed that there is power. Not aware of anyone else in the locality with a similar setup so I could try pscan on the car.

I'm not 100% sure about this but I would guess that the ABS light is on by default and that the ABS module has to be powered up to turn it off.
Essentially any fault will cause the light to come on.
It's easy to prove.  Pull the ABS fuse.  My guess is that the light will still be on.
The other thing is that when I power up my ABS module on a bench power supply I guess a voltage appearing on the wire that goes to the diagnostic plug.
If you don't than that also suggests that maybe the ABS module isn't powered.

Its all OK! I was making the fatal mistake of assuming a serious error, but it was the main supply fuse all along. Replaced that, Pscan now talks to the ECU. No errors reported and the warning light goes out.