964 ABS Lights - No Fault Message
 

My 1990 964C4 is almost 100% fixed after sitting for a few years.

Unfortunately, I still get the ABS light and the AWD light after about 20 seconds of idling, even if I don't move the car, I get the fault.

I previously diagnosed (and repaired) my acceleration sensor using Scantool. But this time there is no stored fault, and I can't connect to the ABS while the car is running. (I'm not sure if this is normal, I connect to Motronic while I'm driving but not the ABS system)

Does anyone know the 'start-up' sequence for the ABS? I am thinking that the fact I get the error without moving means I have a comms problem, or maybe a pump issue? It is probably not wheel speed sensors, as they get checked when you start driving.

I have bled everything, cleaned the pump electrical connector, etc.

Any suggestions? I am out of ideas. :confused: