Antilock Braking System (ABS)

DTC 51 Rear Axle Motor Free Spins:

CIRCUIT DESCRIPTION
This DTC is designed to detect a stripped nut or gear assembly during initialization. During the homing sequence, the piston should reach the top of the bore resulting in a stalled motor. If this does not occur, the motor must be spinning with little or no resistance, indicating a nut/screw or gear failure.

FAILURE CONDITION
DTC A051 can be set during initialization. If the feedback current is less than the command current for a specified period of time, a malfunction exists.

ACTION TAKEN
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 compares feedback current to command current during apply. If either is 0 amps, the EBCM is not functioning properly.
2. This step compares feedback current to command current during release. If either is 0 amps, the EBCM is not functioning properly.
3. Steps 1, 2 and 3 verify malfunction exists. This step also moves the piston to the top of the bore.
4. This step checks for a stripped motor pack gear.
5. This step checks for a stripped hydraulic modulator gear.
6. This test checks the ability of the motor to operator properly when commanded.

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.

If DTC only fails once and DTC A064 also fails, see DTC A064. If intermittent and enhanced diagnostics show this DTC fails during ABS, see DTC A064.

Depending on the frequency of the failure, a physical inspection of the mechanical parts suspected may be necessary.