C1073

C1073-ABS PUMP MOTOR CONTROL CIRCUIT





For a complete wiring diagram Refer to Diagram/Electrical. Electrical Diagrams


- When Monitored:

Continuous

- Set Condition:

The ABM detects low pump motor feedback voltage with actuation of the pump motor relay.








Diagnostic Test


1. CHECK FOR A DTC C1073-ABS PUMP MOTOR CONTROL CIRCUIT

NOTE: This DTC must be active for the results of this test to be valid.

Turn the ignition on.

With the scan tool, record and erase DTCs.

Cycle the ignition switch from off to on.

Road test the vehicle over 40 km/h (25 mph).


NOTE: Vehicle must be driven above 40 km/h (25 mph) for set conditions to be meet.

With the scan tool, read DTCs.


NOTE: The Anti-Lock Brake Module must sense ALL 4 wheels at 12 km/h (7.5 mph) before it will extinguish the ABS indicators.

Does the scan tool display: C1073-ABS PUMP MOTOR CONTROL CIRCUIT?

Yes

- Go To 2

No

- The condition that caused the symptom is currently not present. Inspect the related wiring for a possible intermittent condition. Look for any chafed, pierced, pinched, or partially broken wires.
- Refer to the ABS-INTERMITTENT CONDITION TEST. ABS Intermittent Condition Test



2. INSPECT RELATED WIRING HARNESS, TERMINALS, & CONNECTORS

Turn the ignition off.

Visually inspect the related wiring harness. Look for any pinched, chafed, pierced, and partially broken wires.

Visually inspect the related wiring harness connectors. Look for broken, bent, pushed out, and corroded terminals.

Were any problems found?

Yes

- Repair as necessary.
- Perform ABS VERIFICATION TEST. ABS Verification Test

No

- Go To 3



3. CHECK THE ABS PUMP MOTOR FUSED B+ FOR AN OPEN

Turn the ignition off.

Remove and visually inspect the ABS Pump Motor B+ fuse.

Is the ABS Pump Motor B+ fuse open?

Yes

- Go To 4

No

- Go To 6



4. CHECK THE (A921) FUSED B(+) FOR A SHORT TO GROUND





Turn the ignition off.

Disconnect the Anti-Lock Brake Module harness connector.

Using a 12-volt test light connected to 12-volts, probe the (A921) Fused B+ circuit.

Does the test light illuminate brightly?

Yes

- Repair the (A921) Fused B(+) circuit for a short to ground.
- Perform ABS VERIFICATION TEST. ABS Verification Test

No

- Go To 5



5. CHECK THE (A921) FUSED B(+) CIRCUIT

Turn the ignition off.

Visually inspect the (A921) Fused B(+) circuit in the wiring harness.

Look for any signs of intermittent short to ground.

Is the wiring harness OK?

Yes

- Go To 6

No

- Repair the (A921) Fused B(+) circuit for a short to ground.
- Perform ABS VERIFICATION TEST. ABS Verification Test



6. CHECK THE VOLTAGE ON THE (A921) FUSED B(+) CIRCUIT





Turn the ignition off.

Disconnect the Anti-Lock Brake Module harness connector.

Measure the voltage of the (A921) Fused B(+) circuit in the Anti-Lock Brake Module harness connector.

Is the voltage above 10 volts?

Yes

- Go To 7

No

- Repair the (A921) Fused B(+) circuit for an open.
- Perform ABS VERIFICATION TEST. ABS Verification Test



7. CHECK THE (Z902) GROUND CIRCUITS FOR AN OPEN





Measure the resistance of the (Z902) Ground circuits between the Anti-Lock Brake Module harness connector and ground

Is the resistance below 5.0 ohms?

Yes

- Replace the ICU per service information.
- Perform ABS VERIFICATION TEST. ABS Verification Test

No

- Repair the high resistance in the affected circuit.
- Perform ABS VERIFICATION TEST. ABS Verification Test