C065

Part 1 Of 2:

Part 2 Of 2:

C0265 or C0266 and C065 or C066

CIRCUIT DESCRIPTION (DTC C0265)
The pump motor relay supplies power to all six solenoid coils (three isolation solenoid coils and three dump solenoid coils) and the motor when the ABS is required. The relay and the six solenoid coils are located within the Electronic Brake Control Module (EBCM).

CONDITIONS FOR SETTING THE DTC (DTC C0265)
^ The Electronic Brake Control Module (EBCM) microprocessor commands the relay on
^ Low voltage exists on all six solenoid driver circuits when high voltage is expected (the solenoid is not energized)

CONDITIONS FOR SETTING THE DTC (DTC C0266)
^ The ABS bulb check is complete
^ High voltage exists on the pump motor driver circuit when all are expected to be low (the relay is not commanded on)

ACTION TAKEN WHEN THE DTC SETS
^ The ABS indicator lamp turns on
^ The ABS disables

Diagnostic Trouble Codes (DTCs) C0265 and C0266 are Ignition Latched DTCs, which indicates that the above actions remain true until the ignition is turned to OFF (even if the cause of the DTC is intermittent).

CONDITIONS FOR CLEARING THE DTC
^ Repair the conditions responsible for setting the Diagnostic Trouble Code (DTC)
^ Use the Scan Tool Clear DTCs function

DIAGNOSTIC AIDS (DTC C0265)
Diagnostic Trouble Code (DTC) C0265 usually sets because of an open relay coil or non-closable relay contacts. The relay is located within the Electronic Brake Control Module (EBCM). The relay is not serviceable. If the test does not repair the DTC, then replace the EBCM.
If DTC C0265 appears with other DTCs repair the other DTCs first. Clear all DTCs. Then run three function tests with the Scan Tool Refer to this diagnostic chart if DTC C0265 resets.

DIAGNOSTIC AIDS (DTC C0266)
Diagnostic Trouble Code (DTC) C0266 usually sets when the relay contacts are stuck closed. The relay is located within the EBCM. The relay is not serviceable. If the test does not repair the DTC, then replace the EBCM.

TEST DESCRIPTION
The numbers below refer to the steps in the diagnostic table:
3. This step determines the resistance of the power ground circuit.
4. This step determines the battery voltage available to the Electronic Brake Control Module (EBCM).
7. This step determines the resistance of the signal ground circuit.
8. This step determines the ignition voltage available to the EBCM.