C1218

CIRCUIT DESCRIPTION
Ignition voltage is supplied to terminal 86 of the Electronic Brake Control Relay. The above enables the Electronic Brake Control Module (EBCM) to energize the pull-in coil by completing the ground circuit at connector terminal All 1 of the EBCM. The magnetic field created closes the Electronic Brake Control Relay contacts. The magnetic field also allows battery voltage and current through the Electronic Brake Control Relay terminal 30 to be supplied to the EBCM through connector terminal C. Connector terminal C supplies power to the EBCM, which supplies power to the motors and solenoids.

CONDITIONS FOR SETTING THE DTC
^ Diagnostic Trouble Code (DTC) C1218 can set after the Electronic Brake Control Module (EBCM) commands the Electronic Brake Control Relay ON.
^ This test monitors the availability of voltage to the EBCM.
^ DTC C1286 is set with DTC C1218 if the rear channel is not expected to be in the home position.

ACTION TAKEN WHEN THE DTC SETS
^ A malfunction Diagnostic Trouble Code (DTC) stores.
^ The ABS disables.
^ The ABS warning indicator turns ON.

CONDITIONS FOR CLEARING THE DTC
^ The condition responsible for setting the Diagnostic Trouble Code (DTC) no longer exists and the Scan Tool Clear DTCs function is used.
^ 100 drive cycles pass with no DTCs detected. A drive cycle consists of starting the vehicle, driving the vehicle over 16 km/h (10 mph), stopping and then turning the ignition OFF.

DIAGNOSTIC AIDS
Use the enhanced diagnostic function of the Scan Tool in order to measure the frequency of the malfunction.
Clear the Diagnostic Trouble Codes (DTCs) after completing the diagnosis. Test drive the vehicle for three drive cycles in order to verify that the DTC does not reset. Use the following procedure in order to complete one drive cycle:
1. Start the vehicle.
2. Drive the vehicle over 16 km/h (10 mph).
3. Stop the vehicle.
4. Turn the ignition to the OFF position.

TEST DESCRIPTION
2. This test determines if the Electronic Brake Control Module (EBCM) is capable of controlling the electronic brake control relay as commanded.
3. This test checks for a short to voltage in the switched battery input circuit between the electronic brake control relay and the EBCM.
4. This test checks for an open or high resistance in the electronic brake control relay pull-in coil.
5. This test checks for electronic brake control relay contacts stuck in the closed position.
7. This test determines if the malfunction is caused by the EBCM.

Part 1 Of 2:

Part 2 Of 2:

DTC C1218 BRAKE CONTROL RELAY COIL CIRCUIT SHORT TO VOLTAGE