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 Descriptor

DTC C0820 07: Device Ground 1 Circuit

Circuit/System Description

The electronic brake control module (EBCM) monitors the voltage level of the EBCM case. If the voltage level is too high, damage may result in the system. When the EBCM detects a high voltage condition, the EBCM turns OFF the system relay which removes battery voltage from the solenoid valves and pump motor.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

The case voltage is greater than 2 volts for 0.1 second.

Action Taken When the DTC Sets

If equipped, the following actions occur:

    • The EBCM disables the antilock brake system (ABS) and the vehicle stability enhancement system (VSES) for the duration of the ignition cycle.
    • The dynamic rear proportioning (DRP) and traction control system (TCS) are degraded.
    • The red brake warning indicator illuminates.
    • The ABS indicator illuminates.
    • The traction control off indicator illuminates.
    • The driver information center (DIC) displays the SERVICE STABILITY SYS message.

Conditions for Clearing the DTC

    • The condition for the DTC is no longer present.
    • The electronic brake control module (EBCM) automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

Diagnostic Aids

Possible causes of this DTC are the following conditions:

    • Internal short in the pump motor.
    • External battery supply shorted to case.
    • Internal EBCM battery supply shorted to case.

The pump motor is integral to the 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 for Scan Tool Information

Circuit/System testing

  1. Ignition OFF, disconnect the harness connector at the EBCM.
  2. Test for less than 1.0 ohm of resistance between the ground circuit terminal E and ground.
  3. If not within the specified range, test the ground circuit for an open/high resistance.
  4. Disconnect the pump motor.
  5. Test for infinite resistance between the pump motor terminal and ground.
  6. If not the specified value, replace the BPMV.
    If all circuits test normal, replace the EBCM

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Brake Pressure Modulator Valve Replacement
    •  Control Module References for EBCM replacement, setup, and programming