VEHICLE DESCRIPTION: HEAVY DUTY TRUCKS. THE ANTILOCK TRACTION RELAY VALVES WERE INCORRECTLY ASSEMBLED BY THE SUPPLIER. AN EXTRA CHECK VALVE WAS INSTALLED WHICH WILL NOT ALLOW THE TRACTION CONTROL SYSTEM TO FUNCTION PROPERLY.
THE REAR BRAKES CAN BE APPLIED AUTOMATICALLY DURING A TRACTION EVENT AND NOT RELEASE UNTIL THE AIR SYSTEM PRESSURE IS DEPLETED.
DEALERS WILL INSPECT THESE VEHICLES AND ALL ANTILOCK TRACTION RELAY VALVES FOUND DEFECTIVE WILL BE REPLACED.