67 - Pump Motor Circuit Open

PUMP MOTOR CIRCUIT OPEN-67





For a complete wiring diagram, refer to Wiring Diagram Information.

When Monitored
Ignition on.

Set Condition
Ignition on for at least 3.5 seconds. ABS pump motor command never given during the current ABS command. Low feedback voltage from the low side of the motor.

Possible Causes
- ABS PUMP MOTOR INTERMITTENT DTC
- FUSED B(+) CIRCUIT INTERMITTENTLY SHORTED TO GROUND
- FUSED B(+) CIRCUIT SHORTED TO GROUND
- FUSE OPEN - PUMP MOTOR CIRCUIT
- NO B+ SUPPLY TO FUSE
- ABS PUMP MOTOR INOPERATIVE
- FUSED B(+) CIRCUIT OPEN
- GROUND CIRCUIT OPEN
- GROUND CIRCUIT HIGH RESISTANCE
- CONTROLLER ANTI-LOCK BRAKE

Diagnostic Test
1. DTC IS ACTIVE
Turn the ignition on.
With the DRBIII (R) read DTC's.
With the DRBIII (R) erase DTC's.
Turn the ignition off.
Turn the ignition on.
With the DRBIII (R) actuate the ABS pump motor.

Did the Pump Motor operate when actuated?
Yes >> Go To 10
No >> Go To 2

2. FUSE OPEN - PUMP MOTOR CIRCUIT
Turn the ignition off.
Remove and inspect the ABS Pump Motor fuse.

Is the Fuse open?
Yes >> Go To 3
No >> Go To 5

3. FUSED B(+) CIRCUIT INTERMITTENTLY SHORT
Ensure the Pump Motor connector is secure.
Visually inspect the Fused B(+) circuit in the wiring harness from the ABS PUMP fuse to the CAB harness connector. Look for any signs of an intermittent short to ground.

Is the wiring harness OK?
Yes >> Go To 4
No >> Repair as necessary.
Perform ABS VERIFICATION TEST - VER 1. ABS Verification Test

4. FUSED B(+) CIRCUIT SHORTED TO GROUND
Disconnect the CAB harness connector.
Ensure the ABS Pump Motor connector is secure.
Measure the resistance of the Fused B(+) circuit to ground.

Is the resistance above 5.0 ohms?
Yes >> Replace the Controller Anti-Brake. Refer to the symptom *Replacing the Controller Anti-Lock Brake
Perform ABS VERIFICATION TEST - VER 1. ABS Verification Test
No >> Repair the Fused B(+) circuit short to ground.
Perform ABS VERIFICATION TEST - VER 1. ABS Verification Test

5. FUSED B(+) CIRCUIT OPEN
Remove the ABS PUMP Fuse.
Disconnect the CAB harness connector.
Measure the resistance of the Fused B (+) circuit between the ABS PUMP Fuse Terminal and the CAB harness connector.

Is the resistance below 5.0 ohms?
Yes >> Go To 6
No >> Repair the open in the Fused B(+) circuit.
Perform ABS VERIFICATION TEST - VER 1. ABS Verification Test

6. NO B+ SUPPLY TO FUSE
Turn the ignition on.
Measure the voltage of the B(+) supply at the ABS PUMP Fuse terminal.

Is the voltage above 11 volts?
Yes >> Go To 7
No >> Repair the B(+) Supply circuit.
Perform ABS VERIFICATION TEST - VER 1. ABS Verification Test

7. ABS PUMP MOTOR INOPERATIVE
Turn the ignition off.
Disconnect the ABS Pump Motor connector.
Connect a 10 gauge jumper wire between ABS Pump Motor Fused B(+) circuit and a 40 Amp Fused B(+) circuit.
Connect a 10 gauge jumper wire between ABS Pump Motor ground circuit and ground.
Monitor ABS Pump Motor operation.

Is the ABS Pump Motor operating?
Yes >> Go To 8
No >> Replace the ABS Pump Motor/Hydraulic Control Unit assembly.
Perform ABS VERIFICATION TEST - VER 1. ABS Verification Test

8. GROUND CIRCUIT OPEN
Turn the ignition off.
Disconnect the CAB harness connector.
Measure the resistance of the CAB Ground circuits.

Is the resistance below 5.0 ohms?
Yes >> Go To 9
No >> Repair the open in the Ground circuit.
Perform ABS VERIFICATION TEST - VER 1. ABS Verification Test

9. GROUND CIRCUIT HIGH RESISTANCE
Make sure the ABS Pump Motor connector is secure.
Turn the ignition on.
With the DRBIII (R) enable ABS Pump Motor actuation.

NOTE: NOTE: ABS Pump Motor will not operate, but voltage will be applied.

Measure the voltage drop across the ABS Ground circuit connection, with ABS Pump Motor actuation enabled.

Is the voltage below 0.1 volt?
Yes >> Replace the Controller Anti-Lock Brake.
Perform ABS VERIFICATION TEST - VER 1. ABS Verification Test
No >> Repair the high resistance in the Ground circuit.
Perform ABS VERIFICATION TEST - VER 1. ABS Verification Test

10. WIRING HARNESS INSPECTION
Turn the ignition off.
Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or partially broken wires.
Make sure the Pump Motor connector is secure.
Visually inspect the related wire harness connectors. Look for broken, bent, pushed out, or corroded terminals.
Refer to any Technical Service Bulletins that may apply.

Were any problems found?
Yes >> Repair the Left Front Wheel Speed Sensor Signal circuit for a short to voltage.
Perform ABS VERIFICATION TEST - VER 1. ABS Verification Test
No >> Test Complete.