DTC 42

DTC 42 Rear ESB Will Not Hold Motor:

Circuit Description:
This DTC is designed to detect a slipping rear ESB. During initialization and braking, the rear motor is re-homed. If the ESB slips, the motor/piston will move. During the next initialization, a re-home of the motor verifies the motor/piston remained at the home position. If motor movement is detected, the ESB must be slipping.

DTC Will Set When:
DTC 42 can be set during initialization. DTC 86 is always set with DTC 42.

Action Taken:
If an ESB cannot hold a motor in the home position, the motor may be back driven when the brake pedal is applied causing the brake pedal to drop. A malfunction DTC is stored, ABS is disabled and the ABS indicator lamp is turned "ON."

DTC Chart Test Description:
Number(s) below refer to circled number(s) on the diagnostic chart.
1. This step ensures motor circuits are in the proper connector cavity.
2. This step checks the rear ESB. A broken or defective ESB would result in the rear piston being back driven by hydraulic pressure, and wheel movement would result.
3. Checks for high resistance in the rear motor high circuit.
4. Checks for high resistance in the rear motor low circuit.
5. Checks for excessive resistance in the rear motor.
6. Ensures malfunction was not due to a poor connection.

Diagnostic Aids:
An "intermittent" malfunction in this DTC may result from a mechanical part of the system that sticks, binds, or slips.

The frequency of the malfunction can be checked by using the enhanced diagnostic function of the Tech 1.