I know in an earlier post you said you'd checked the tires, but are they all the same size with same/similar wear amount? Heard of some having the TOD get cranky when the tires are too far different in circumference....but not sure if it throws a code or not. Any clunking / nasty noises?
On the ABS...if it does turn out to be an ABS wheel sensor...they're like $500 smackers new from Isuzu......so I got mine from a Trooper in a junkyard for $80 including delivery (actual delivery to my mechanic)...just FYI...
Had another thought.....since this is the first I've heard of someone that actually got the ABS unit rebuilt...could it be something with the rebuild that's not reading correctly and causing it to throw a code?