GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The electronic brake control module (EBCM) monitors the deceleration of the vehicle for antilock brake system (ABS) operation.

Conditions for Running the DTC

The vehicle speed is greater than 5 km/h (3 mph).

Conditions for Setting the DTC

The EBCM detects an open or a short in the deceleration sensor circuitry.

Action Taken When the DTC Sets

The ABS warning indicator turns ON.

Conditions for Clearing the DTC

The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.

Diagnostic Aids

Thoroughly inspect the wiring and the connectors. An incomplete inspection of the wiring and the connectors may result in a misdiagnosis, causing a part replacement with the reappearance of the malfunction.

The following are possible causes of the malfunction:

    • An open or short in deceleration sensor to EBCM wiring circuits
    • An open or high resistance in the ignition positive voltage circuit
    • An open or high resistance in the deceleration sensor ground circuit
    • A deceleration sensor malfunction
    • An internal EBCM malfunction

If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step uses the scan tool to test the ignition positive voltage circuit to the EBCM.

Step

Action

Value(s)

Yes

No

Schematic Reference: Antilock Brake System Schematics

Connector End View Reference: Antilock Brake System Connector End Views

1

Did you perform A Diagnostic System Check - ABS?

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Go to Step 2

Go to Diagnostic System Check - ABS

2

  1. Turn ON the ignition, with the engine OFF.
  2. With a scan tool, observe the deceleration sensor parameter in the ABS data list.

Does the scan tool indicate the deceleration sensor is within the specified range?

Low

Go to Diagnostic Aids

Go to Step 3

3

Test the deceleration sensor circuits of the EBCM for a high resistance, an open, or a short. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 7

Go to Step 4

4

Test the voltage of the deceleration sensor circuits of the EBCM to a good ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Is the voltage within the specified range?

Terminal GS1 and GS2: approximately 5 V

Terminal GST: switching between 0 and 12 V

Go to Step 5

Go to Step 6

5

Replace the deceleration sensor. Refer to Deceleration Sensor Replacement .

Did you complete the replacement?

--

Go to Step 7

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6

Replace the brake pressure modulator valve (BPMV). Refer to Brake Pressure Modulator Valve Assembly Replacement .

Did you complete the replacement?

--

Go to Step 7

--

7

  1. Use the 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 2

System OK