C1258

DTC C1258 (1 Of 2):

DTC C1258 (2 Of 2):

CIRCUIT DESCRIPTION
This DTC identifies an ABS motor circuit that is shorted to voltage or an ABS motor that has low or no resistance. This malfunction will not allow the ABS motor to be controlled at the commanded current rate or will cause the ABS motor to turn in the opposite direction, or not at all.

CONDITIONS FOR SETTING THE DTC
DTC C1258 can be set only when the ABS motor is commanded off. If the EBCM detects an out of range voltage on either of the left front ABS motor circuits indicating a circuit shorted to voltage or an ABS motor internally shorted, a malfunction exists.

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
Using the scan tool, select manual control function, and exercise ABS motor movement of the affected channel in both directions while applying light pressure on the brake pedal. If erratic or jumpy brake pedal movement is detected while performing an apply or release function of the ABS motor, an intermittent malfunction may be indicated. An intermittent malfunction may be caused by a poor connection, rubbed through wire insulation, or a wire that is broken inside the insulation. IF the malfunction is not current, wiggle the wires of the affected channel and check if the DTC resets. This will help to pinpoint an intermittent malfunction in the motor circuitry or connections. The frequency of the malfunction can be checked by using the enhanced diagnostic function of the scan tool. 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.

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.