C1218

Circuit Description
The system relay is energized when the ignition is ON. The system relay supplies voltage to the solenoid valves and the pump motor. This voltage is referred to as the system voltage.
The EBCM controls the each solenoid valve by grounding the solenoid.
The EBCM controls the pump motor by grounding the control circuit. The pump serves 2 purposes:
^ Transfers brake fluid from the brake calipers to the master cylinder reservoir during pressure decrease events.
^ Transfers brake fluid from the master cylinder reservoir to the brake calipers during pressure increase events.

Conditions for Running the DTC
^ The pump motor is commanded ON.
^ The system voltage is greater than 8 volts.

Conditions for Setting the DTC
One of the following conditions exists for 0.5 seconds:
^ With the commanded pump motor voltage less than the system voltage, the actual pump motor voltage is 3 volts less than the commanded voltage.
^ With the commanded pump motor voltage greater than the system voltage, the actual pump motor voltage is less than 8 volts.

Action Taken When the DTC Sets
If equipped, the following actions occur:
^ The EBCM disables the ABS/TCS/VSES for the duration of the ignition cycle.
^ The DRP does not function optimally.
^ The ABS indicator turns ON.
^ The TRACTION CONTROL indicator turns ON.
^ The DIC displays the SERVICE STABILITY SYS message.

Conditions for Clearing the DTC
^ The condition for the DTC is no longer present (the DTC is not current) and you used the scan tool Clear DTC function.
^ The condition for the DTC is no longer present (the DTC is not current) and you used the On-Board Diagnostics Clear DTC function.
^ The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

Diagnostic Aids
The pump motor is integral to the BPMV. The pump motor is not serviceable.

Test Description
The number below refers to the step numbers on the diagnostic table.
3. Tests the ability of the EBCM to control the pump motor. If the test lamp illuminates, the pump motor circuit within the EBCM is good.