GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The pump motor is grounded through the ground stud on the BPMV. The EBCM controls the pump motor by energizing the pump motor relay. The pump motor relay then supplies voltage to the pump motor. The pump serves 2 purposes:

    • Transfers brake fluid from the brake calipers to the master cylinder reservoir during pressure decrease events.
    • Transfers brake fluid from the master cylinder reservoir to the brake calipers during pressure increase events.

Conditions for Running the DTC

    • The ignition voltage is greater than 10.5 volts.
    • The relay is commanded ON.

Conditions for Setting the DTC

The relay voltage is less than 8 volts.

Action Taken When the DTC Sets

If equipped, the following actions occur:

    • The EBCM disables the ABS/TCS/VSES for the duration of the ignition cycle.
    • The ABS indicator turns ON.
    • The Traction Control indicator turns ON.
    • The DIC displays the Service Stability System message.

Conditions for Clearing the DTC

    • The condition for the DTC is no longer present (the DTC is not current) and you used the scan tool Clear DTC function.
    • The condition for the DTC is no longer present (the DTC is not current) and you used the On-Board Diagnostics Clear DTC function.
    • The EBCM automatically clears the history DTC when a current DTC is not detected in 50 consecutive drive cycles.

Diagnostic Aids

The relays are integral to the EBCM. The relays are not serviceable.

Test Description

The number below refers to step number on the diagnostic table.

  1. Tests for an internal short in the BPMV.

Step

Action

Values

Yes

No

Schematic Reference: Antilock Brake System Schematics

1

Did you perform the ABS Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - ABS

2

Inspect the RH underhood fuse block BRAKES (50 A) Fuse.

Is the fuse OK?

--

Go to Step 6

Go to Step 3

3

  1. Install a new BRAKES (50 A) Fuse.
  2. Turn OFF the ignition.
  3. Turn ON the ignition, with the engine OFF.
  4. Use a scan tool in order to select ABS/TCS Delco Bosch Special Functions.
  5. Run the Automated Test.
  6. Inspect the BRAKES (50 A) Fuse.

Is the fuse OK?

--

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 4

4

  1. Turn OFF the ignition.
  2. Remove the BRAKES (50 A) Fuse.
  3. Disconnect the EBCM connector.
  4. Disconnect the BPMV ground.
  5. Connect the J 39700 universal pinout box using the J 39700-25 cable adapter to the EBCM harness connector only.
  6. Test both battery supply circuits for a short to ground.

Did you find and correct the condition?

--

Go to Step 9

Go to Step 5

5

  1. Remove the EBCM from the BPMV.
  2. Connect the J 41247 pinout box to the BPMV.
  3. Measure the resistance between the solenoid power control circuit and the BPMV case.

Is the resistance within the specified range?

OL (Infinite)

Go to Step 7

Go to Step 8

6

  1. Turn OFF the ignition.
  2. Remove the BRAKES (50 A) Fuse.
  3. Disconnect the EBCM connector.
  4. Disconnect the BPMV ground.
  5. Connect the J 39700 universal pinout box using the J 39700-25 cable adapter to the EBCM harness connector only.
  6. Test both battery supply circuits for an open or a high resistance.

Did you find and correct the condition?

--

Go to Step 9

Go to Step 7

7

Replace EBCM. Refer to Electronic Brake Control Module Replacement .

Did you complete the repair?

--

Go to Step 9

--

8

Replace the BPMV. Refer to Brake Pressure Modulator Valve Replacement .

Did you complete the repair?

--

Go to Step 9

--

9

  1. Use the scan tool in order to clear the DTCs.
  2. With the scan tool, perform the Automated Test.

Does the DTC reset?

--

Go to Step 2

System OK