DTC A056: Left Front Motor Circuit Open

LEFT FRONT MOTOR CIRCUIT OPEN





Circuit Description
This DTC identifies a motor that cannot be energized due to an open in its circuitry.

Diagnosis
This test will detect an open in the left front motor circuit any time the motor is off and the system is enabled.

Cause(s)
- An open exists in the wiring from the electronic brake control module (EBCM) to the motor.
- The motor armature winding is open or has high resistance.
- There is a poor contact at the EBCM or at the motor pack connector.
- The EBCM is faulty.

Fail Action
This is a critical operational fault. The ABS is disabled and the ABS warning lamp is turned on. A rehome is commanded on the other two channels to ensure that they are in the home position.

Test Description
The number(s) below refer to step(s) on the diagnostic table.
2. This step checks for proper resistance of the motor.
3. This step checks for an open in the motor feed circuitry-
4. This step checks for an open in the motor return circuitry.

Diagnostic Aids
Select the manual control function of the scan tool to exercise 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 a RELEASE function on the motor, an intermittent malfunction may be indicated.
An intermittent malfunction may be caused by a poor connection, wire insulation that has been rubbed through, 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 the connections.
Check the frequency of the malfunction by using the enhanced diagnostic feature of the scan tool as described in "Scan Tool Diagnostics." Scan Tool Diagnostics
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 damage to the wiring harness.





DTC A056 - Left Front Motor Circuit Open