GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The ABS pump motor voltage supply circuit is switched ON and OFF by the EBCM to control pump motor function.

Conditions for Running the DTC

    • The ignition is ON.
    • The vehicle speed is greater than 20 km/h (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

If equipped, the following actions occur.

    • The EBCM disables ABS/TCS.
    • The ABS indicator turns ON.
    • The traction off indicator turns ON.

Conditions for Clearing the DTC

The conditions for setting the DTC are no longer present and you use the scan tool Clear DTCs function.

Diagnostic Aids

Separate the EBCM from the 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 Testing for Intermittent Conditions and Poor Connections . If severe corrosion or other damage exists, the BPMV or the EBCM may need to be replaced.

Test Description

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

  1. This step tests if the EBCM is capable of activating the ABS pump motor.

Step

Action

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

  1. Use a scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC set?

Go to Step 3

Go to Diagnostic Aids

3

  1. Turn OFF the ignition.
  2. Separate the EBCM from the BPMV. Refer to Electronic Brake Control Module Replacement .
  3. Connect a test lamp between the ABS pump motor power and ground circuits at the pump motor connector of the EBCM.
  4. Turn ON the ignition.
  5. Use the scan tool in order to clear the DTCs.

Does the DTC clear and then remain cleared while the test lamp is connected?

Go to Step 4

Go to Step 6

4

Use the scan tool in order to perform an ABS Motor test.

Does the test lamp illuminate and then turn OFF when the ABS Motor test is performed?

Go to Step 5

Go to Step 8

5

Inspect for poor connections at the pump motor connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 7

6

Important: Following EBCM replacement, use the scan tool to perform the Tire Size/Wheel Base Calibration procedure.

Replace the EBCM. Refer to Electronic Brake Control Module Replacement .

Did you complete the replacement?

Go to Step 9

--

7

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

Did you complete the replacement?

Go to Step 9

--

8

Important: Following EBCM replacement, use the scan tool to perform the Tire Size/Wheel Base Calibration procedure.

Replace the EBCM and the BPMV. Refer to Electronic Brake Control Module Replacement and Brake Pressure Modulator Valve Replacement .

Did you complete the replacements?

Go to Step 9

--

9

  1. Use a scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 3

System OK