C1215

(Part 1 Of 4):

(Part 2 Of 4):

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Schematic Diagram:

CIRCUIT DESCRIPTION
When the ignition is first turned to RUN, the Electronic Brake/Traction Control Module (EBCM/EBTCM) goes through a self-check lasting 2-4 seconds. During this test the EBCM/EBTCM grounds terminal 34, energizing the main relay. Once the self-check is completed the main relay remains energized. This delivers battery voltage to both the EBCM/EBTCM and the Brake Pressure Modulator Valve (BPMV) during vehicle operation. The constant voltage supply allows the vehicle to enter ABS mode without delay. The main relay is de-energized whenever the amber ANTILOCK indicator illuminates due to a system malfunction, causing the ABS to shut down.

CONDITIONS FOR SETTING THE DTC
DTC C1215 sets when the ignition switch is in RUN and EBCM/EBTCM detects a failure with any one of the valves, but can not determine which valve is faulted.

ACTION TAKEN WHEN THE DTC SETS
A malfunction DTC is stored, ABS is disabled and the ANTILOCK indicator lamp is turned ON.

CONDITIONS FOR CLEARING THE DTC
^ Conditions for the malfunction are no longer present and scan tool clear DTCs function is used.

^ 100 ignition switch key cycles have passed with no malfunctions detected.

DIAGNOSTIC AIDS
Possible Causes:
- Open in any inlet or outlet valve circuit.
- Short to ground in any inlet or outlet valve circuit.
- High resistance in any inlet or outlet valve circuit and if equipped with traction control, high resistance in either isolation valve circuit.

TEST DESCRIPTION
The numbers below refer to step numbers on the diagnostic table.

2. Checks for an open power feed for the solenoids internal to the BPMV.
3. Ensures that the BPMV is not internally shorted to ground.
4. Checks the resistance of all solenoids.
5. Rechecks the resistance of the solenoids through the wiring harness between the EBCM/EBTCM and the BPMV.
10. Checks the integrity of CKT 1633 to the EBCM/EBTCM and the BPMV.