C1257

DTC C1257: Left Front ABS Motor Circuit Shorted To Ground (Part 1 Of 2):

DTC C1257: Left Front ABS Motor Circuit Shorted To Ground (Part 2 Of 2):

DTC C1257 Schematic:

Circuit Description
This DTC identifies a motor circuit that is shorted to ground. A short to ground motor will not allow controlled ABS operation.

Conditions for Setting the DTC
This DTC will set when the following conditions are met:
^ The Electronic Brake Control Module (EBCM) detects a short to ground in CKT 1280 and/or 1281.
^ This DTC can be set anytime.

Action Taken When the DTC Sets
A malfunction DTC is stored, ABS is disabled, and the amber ABS indicator lamp is turned ON.

Conditions for Clearing the DTC
^ Conditions for the malfunction are no longer present and the Tech 2 scan tool Clear DTC Information function is used.
^ One hundred drive cycles have passed with no malfunctions detected.

Diagnostic Aids
The following list contains items that need to be inspected when diagnosing this system:
^ Short to ground between the left front motor and the EBCM (CKT 1280 and/or CKT 1281).
^ Left front motor armature winding grounded (low resistance to ground).
^ Faulty EBCM.
An intermittent malfunction is most likely caused by a rubbed through wire insulation or a short to ground within the motor.

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 Tech 2 scan tool, as described in Enhanced Diagnostics.



Test Description
Numbers below refer to numbers on the diagnostic table.
3. Checks for a short to ground in CKT 1280.
4. Checks for a short to ground in CKT 1281.
14. Checks for an erratic or jumpy motor.