I had an interesting situation with my 02 XKR... my car had no errors or signs of problems at all except for an inaccurate gas gauge (caused by a bad sending unit, which I haven't gotten around to replacing yet) and occasional ABS/traction control errors. I assumed that the errors were caused by a wheel sensor cable going bad, because they would come and go randomly.
Then one day my car started throwing every error code under the sun starting with ABS and continuing on to every other light, my transmission went into limp mode, and I barely made it home. My alternator had died. I replaced it with a nice Denso rebuilt unit, and ever since then I haven't seen another ABS error code. So it seems to me that my original problem was that the alternator was cutting out momentarily, triggering the ABS codes due to low voltage. The only way I could have caught this would be if I had a voltmeter hooked up where I could see it while driving, so that I could hopefully notice the voltage dropping at the same time an ABS error appeared.
So if you are on the hunt for random ABS errors and nothing else seems to be the cause, try driving around with a voltmeter hooked up and see if your alternator may be on the way out! :-)