C1266

DTC C1266: Rear ABS Motor Circuit Shorted To Voltage (Part 1 Of 2):

DTC C1266: Rear ABS Motor Circuit Shorted To Voltage (Part 2 Of 2):

DTC C1266 Schematic:

Circuit Description
This DTC identifies a motor circuit that is shorted to voltage.

Conditions for Setting the DTC
This DTC will set when the following conditions are met:
^ The Electronic Brake Control Module (EBCM) detects a short to voltage in CKT 1284 and/or CKT 1285.
^ This DTC can be set anytime.

Action Taken When the DTC Sets
A malfunction DTC is stored, ABS is disabled, and the amber ABS indicator lamp is turned ON. The red BRAKE warning lamp is turned ON if the rear piston in the motor pack is not expected to be in the home position.

Conditions for Clearing the DTC
^ Conditions for the malfunction are no longer present and the Tech 2 scan tool Clear DTC Information function is used.
^ One hundred drive cycles have passed with no malfunctions detected.

Diagnostic Aids
The following list contains items that need to be inspected when diagnosing this system:
^ Short to voltage between the rear motor and the EBCM (CKT 1284 and/or CKT 1285).
^ Rear motor armature winding has low or no resistance.
^ Faulty EBCM.
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 2 scan tool, as described in Enhanced Diagnostics.


Test Description
The numbers below refer to step numbers on the diagnostic table.
4. Checks for a short to voltage in CKT 1284.
5. Checks for a short to voltage in CKT 1285.
6. Checks for shorted together CKT 1284 and 1285.
7. Checks for rear motor resistance.