DTC 66

66 REAR ABS MOTOR CIRCUIT SHORTED TO BATTERY

DTC 66 Rear ABS Motor Circuit Shorted To Battery:

DTC 66 Rear ABS Motor Circuit Shorted To Battery:

Circuit Description:
This DTC identifies an ABS motor circuit that is shorted to battery or an ABS motor that has low or zero resistance. This malfunction will not allow the ABS motor to be controlled at the commanded current rate or will cause the ABS motor to turn in the opposite direction or not turn at all.

DTC Will Set When:
DTC 66 can be set only when the ABS motor is commanded "OFF." If the EBCM detects an out of range voltage on either of the rear ABS motor circuits indicating a circuit shorted to battery or an ABS motor shorted, a malfunction exists.

Action Taken:
A malfunction DTC is stored, ABS is disabled and the amber ABS warning lamp is turned "ON." If the rear axle motor is not in home position then the red BRAKE warning lamp is turned "ON."

DTC Chart Test Description:
Number(s) below refer to circled number(s) on the diagnostic chart.
1. Checks for a short to voltage in the ABS motor "HIGH" circuitry.
2. Checks for a short to voltage in the ABS motor "LOW" circuitry.
3. Checks for a short circuit between ABS motor "HIGH" and ABS motor "LOW."
4. Checks for proper resistance of the ABS motor.
5. Ensures malfunction was not due to physical damage of the circuitry.

Diagnostic Aids:
Using Tech 1, select manual control function and exercise ABS motor movement of 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 "release" function of the ABS motor, an intermittent malfunction may be indicated.

An "Intermittent" malfunction may be caused by a poor connection, rubbed through wire insulation, 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 connections.

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

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.