C0068

ABS/Pump Motor Circuit Schematic:

CIRCUIT DESCRIPTION
The pump motor circuit is integral to the Electro-Hydraulic Control Unit (EHCU). The EBCM microprocessor energizes the relay within the Electronic Brake Control Module (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 DTC
^ Vehicle speed 13 km/h (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 indicator lamp is illuminated
^ ABS is disabled

NOTE: Diagnostic Trouble Code (DTC) C0068 This DTC is an ignition latched DTC which indicates the above is true until the ignition is turned to "OFF" (even if the cause of the DTC is intermittent).

CONDITIONS FOR CLEARING THE DTC
^ Conditions for setting the DTC are repaired and the Scan Tool clear (DTCs) function is used.

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. If the pump motor is found to be damaged, the BPMV must be replaced.

NOTE: The J 39200, or equivalent tester, leads must be "zeroed" prior to making any resistance measurements. Refer to the testers operators manual.

DTC 68 Pump Motor Locked Or Pump Motor Circuit Shorted (Part 1 Of 2):

DTC 68 Pump Motor Locked Or Pump Motor Circuit Shorted (Part 2 Of 2):

TEST DESCRIPTION
The numbers below refer to the step numbers on the chart.
[3] Checks the resistance of the pump motor.
[5] Checks the resistance of the pump motor ground circuit.
[6] Checks the voltage available to the pump motor circuit.