C1254

DTC C1254 (1 Of 2):

DTC C1254 (2 Of 2):

CIRCUIT DESCRIPTION
This DTC will diagnose an ABS motor that is energized longer than expected. This could occur if a wheel speed sensor is malfunctioning, the ABS motor does not turn, or the ABS motor wires are crossed.

CONDITIONS FOR SETTING THE DTC
DTC C1254 can be set only during an ABS stop. A malfunction exists if the EBCM commands the rear channel in release for greater than three seconds and a difference of greater than 11 km/h (7 mph) exists between the vehicle reference speed and the maximum rear axle wheel speed. A malfunction exists if the EBCM commands the rear channel in release for greater than four seconds and a difference of less than 11 km/h (7 mph) exists between the vehicle reference speed and the maximum rear axle wheel speed.

ACTION TAKEN WHEN THE DTC SETS
A malfunction DTC is stored, ABS is disabled, and the amber ABS warning indicator is turned on.

DIAGNOSTIC AIDS
An intermittent malfunction may be caused by a mechanical part of the system that sticks or binds. The frequency of the malfunction can be checked by using the enhanced diagnostic function of the scan tool. Using the scan tool, perform hydraulic test to ensure total brake system is functional. Any circuitry that is suspected of causing the intermittent complaint should be thoroughly checked for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wiring connections, or physical darnage to the wiring harness.

NOTE: J 39200 test leads must be zeroed prior to making any resistance measurements. Refer to J 39200 user's manual.

After diagnosis is complete, clear the DTCs and test drive the vehicle for three drive cycles to verify that the DTC does not reset. A drive cycle consists of starting the vehicle, driving the vehicle over 16 km/h (10 mph), stopping and then turning the ignition off.

NOTE: Excessive drag or high resistance in the base brake or suspension system must be inspected and corrected before proceeding with DTC diagnosis.