GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC C0110: Pump Motor Circuit

Circuit/System Description

The Antilock Brake System (ABS) pump motor voltage supply circuit is switched ON and OFF by the electronic brake control module (EBCM) to control pump motor function.

Conditions for Running the DTC

    • The ignition is ON.
    • The vehicle speed is greater than 20 k/mh (13 mph).

Conditions for Setting the DTC

The EBCM detects any of the following conditions:

    •  An open or shorted pump motor.
    •  An open or shorted pump motor driver circuit.
    • A seized pump motor.

Action Taken When the DTC Sets

    • The EBCM disables the ABS/Traction Control System (TCS).
    • The ABS indicator turns ON.
    • The traction off indicator turns ON.

Conditions for Clearing the DTC

    • The condition for the DTC is no longer present and the DTC is cleared with a scan tool.
    • The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

Diagnostic Aids

Seperate the EBCM from the brake pressure modulator valve (BPMV) in order to inspect for corrosion or any other condition that may cause a poor connection at the pump motor connector. Refer to Electronic Brake Control Module Replacement and Brake Pressure Modulator Valve Replacement. If severe corrosion or other damage exists, the BPMV or the EBCM may need to be replaced. The pump motor is integral to the brake pressure modulator valve (BPMV). The pump motor is not serviceable.

Reference Information

Schematic Reference

Antilock Brake System Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

ABS Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References

Circuit/System Testing

  1. Ignition OFF, disconnect the EBCM harness connector and connect a test lamp between the battery positive voltage circuit terminal going to the Power Brake (P/B) Booster Pump Motor, and to ground.
  2. Ignition ON, verify that the test lamp illuminates.
  3. If the test lamp does not illuminate, repair the open or high resistance in the battery positive voltage circuit.
  4. Connect a test lamp between the battery positive voltage circuit and pump motor ground circuit at the EBCM connector, verify that the test lamp illuminates.
  5. If the test lamp does not illuminate, repair the open or high resistance in the pump motor ground circuit.
  6. Ignition OFF, remove the EBCM from the BPMV.
  7. Inspect the EBCM to BPMV connector for conditions such as damage, corrosion, or presence of brake fluid.
  8. If connector corrosion or damage is evident, replace BPMV and/or EBCM as necessary.
    If brake fluid is present, replace both BPMV and EBCM.
  9. Connect the EBCM harness to the EBCM with the BPMV still separated.
  10. Connect a test lamp between the pump motor circuits, internal EBCM side.
  11. Ignition ON, use the scan tool to perform the Pump Motor Test.
  12. If test lamp illuminates replace the BPMV.
    If test lamp does not illuminate replace the EBCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Electronic Brake Control Module Replacement
    •  Control Module References for EBCM replacement, setup, and programming