A042

Circuit Description
This DTC is designed to detect a slipping rear axle ESB. During initialization and braking, the rear motor is re-homed. If the ESB slips, the motor/piston will move. During the next key on 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.

Failure Condition
DTC A042 can be set during initialization. DTC A086 is always set with A042.

Action Taken
If an ESB can not hold a motor in the home position, the motor may be backdriven 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."

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 axle ESB. A broken or defective ESB would result in the rear piston being back driven by hydraulic pressure, and wheel movement would result.
3. This step is used to release the tension of the motor pack prior to removal.

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 as described in "Diagnosis-Electrical."

The static modulator test function of the Tech 1 may be used to locate an intermittent malfunction associated with the ESB.