C0068

Electronic Brake Control Module (EBCM) Power And Ground:

DTC C0068 - Pump Motor Locked Or Pump Motor Circuit Shorted:

CIRCUIT DESCRIPTION
The pump motor circuit is integral to the Electronic Brake Control Module (EBCM). The EBCM microprocessor energizes the relay within the EBCM to supply battery voltage to the high side of the pump motor. When pump motor activation is required, the EBCM microprocessor grounds the low side of the pump motor.

CONDITIONS FOR SETTING THE DIAGNOSTIC TROUBLE CODE (DTC)
^ Vehicle speed 8 mph or greater
^ EBCM internal relay on
^ Pump motor commanded on and then off
^ High voltage from low side of pump motor for 100ms when expected to be low

ACTION TAKEN WHEN THE DTC SETS
^ Antilock Brake System (ABS) indicator lamp is illuminated
^ ABS is disabled

NOTE: This DTC is an Ignition Latched DTC, which indicates that the above is true until the ignition switch is turned to Off position (even if the cause of the DTC is intermittent).

DIAGNOSTIC AIDS
DTC C0068 is usually caused by a seized pump motor, but also can be caused by shorted pump motor windings or by poor power/ground at the 2-way EBCM connector. The pump motor is integral with the Brake Pressure Modulator Valve (BPMV) assembly and cannot be separately serviced. The EBCM or BPMV must be replaced if these tests show the pump motor EBCM internal circuitry has failed.

NOTE: Test leads from the J 39200, or equivalent, must be zeroed prior to making any resistance measurements. Refer to the tool user's manual.

TEST DESCRIPTION

NOTE: Number(s) below refer to number(s) on the diagnostic chart.

3. Check for a shorted pump motor circuit. The pump motor circuit resistance should not be below 0.1 ohm. The J 39200 (or equivalent) test leads must be zeroed prior to making this low resistance measurement.
5. Check the resistance of the EBCM ground circuit.
7. Check the ignition voltage available to the EBCM.