DTC A041: Right Front Esb Will Not Hold Motor

RIGHT FRONT ESB WILL NOT HOLD MOTOR





Circuit Description
This DTC is designed to detect a slipping right front expansion spring brake (ESB). During initialization and braking, the right front motor is rehomed. If the ESB slips, the motor/piston will move. During the next ignition ON initialization, a rehome of the motor verifies that the motor/piston remained at the home position. If motor movement is detected, the ESB must be slipping.

Diagnosis
This test checks to see if the modulator is in the home position at ignition ON. If forward motor movement is detected and the modulator piston was expected to be at the home position, this fault is registered. This failure is detected if the motor sense current is less than the stall current (10.7 amps).

Cause(s)
- There has been a mechanical failure in the ESB.
- There is high resistance in the motor.
- The motor pack assembly is malfunctioning.
- A piston is sticking and not returning to the home position.

Action Taken
This is a critical operational fault as the driver might backdrive the motor when applying the brake, causing the brake pedal to drop. The ABS is disabled and the ABS warning lamp is turned on.

Test Description
The number(s) below refer to step(s) on the diagnostic table.
1. This step checks the right front ESB. A broken or defective ESB would result in the right front piston's being backdriven by hydraulic pressure, and pedal movement would result.
3. This test checks for high resistance in the right front motor feed circuit,
4. This test checks for high resistance in the right front motor return circuit.
5. This test checks for high resistance in the right front motor.
6. This test determines if the fault is due to poor terminal contact or corrosion.
8. This test determines if the fault is due to a faulty electronic brake control module (EBCM).

Diagnostic Aids
An intermittent malfunction in this DTC may result from a mechanical part of the system that sticks, binds, or slips.
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
Use the static modulator test function of the scan tool to locate an intermittent malfunction associated with the ESB.





DTC A041 - Right Front ESB Will Not Hold Motor