The one thing I know of that can affect all the ECU systems is the infamous OVP relay , any system faults where the ABS light comes on I would look here first, it's a tall silver relay in the ECU compartment at the rear of the engine bay. It's function is to protect the ecu's in event of a voltage surge ,there are two fuses on top which may have blown, but if your relay is made by Seimens it may have broken down internally and need to be replaced.
Hope this helps, Geo.