C1256

EBCM/Motor Pack Schematic:

CIRCUIT DESCRIPTION
This Diagnostic Trouble Code (DTC) identifies a motor that cannot be energized due to an open in its circuitry. This malfunction will not allow proper front ABS operation because an open motor will not activate when requested.

CONDITIONS FOR SETTING THE DTC
This DTC will set when the following conditions are met:
^ The Electronic Brake Control Module (EBCM) detects an open in CKT 9C01 and/or CKT 9D01.
^ This DTC can be set only when the motor is OFF (no motor movement).

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:
^ Open or high resistance in between the left front motor and the EBCM (CKT 9C01/CKT 9D01).
^ Faulty motor pack (left front motor armature winding open).
^ Faulty EBCM.

NOTE: An intermittent malfunction is most likely 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 Tech 2 scan tool, as described in Enhanced Diagnostics.

Inspect The Following Harness Connectors For - backed-out terminals, improper rating, broken locks, improperly formed or damaged terminals, poor terminal to wiring connections or physical damage to the wiring harness before component replacement:
^ Motor pack connector.
^ EBCM connector C1.

DTC C1256 Left Front ABS Motor Circuit Open (Part 1 Of 2):

DTC C1256 Left Front ABS Motor Circuit Open (Part 2 Of 2):

TEST DESCRIPTION
Numbers below refer to numbers on the diagnostic table.
[3] Checks motor resistance.
[4] Checks for an open in CKT 9C01.
[5] Checks for an open in CKT 9D01.
[14] Checks for an erratic or jumpy motor.