Faber, what did this turn out to be? I have a different code (524225-0 & 524269-7) but similar symptoms...trucks runs and lifts, but in forward shows fault and "truck disabled" message. I understand my situation is related to transmission issue, possibly pressure level, but wondering what you looked at and finally found out. Thanks.
Check the TISS/TOSS sensors and wiring. Try a calibration.