[Chameleon-kat]

I assume you mean the ABS light comes on when you brake. I believe it may take a dealer scanner to point to a particular wheel the system is complaining about, and the first thing it will suggest is sensor being bad (meaning replacement of bearing hub assembly), but in many cases it is due to bad connection to sensor (corroded or whatever) or broken wire. It is also possible there is water intrusion/corrosion in a connector underneath vehicle just to rear of drivers seat that has been known to cause troubles.