GM Service Manual Online
For 1990-2009 cars only

Circuit Description

When the brake switch is closed (brake released), the master cylinder pressure sensor signal voltage is low. When the brake switch is open, the master cylinder pressure sensor signal voltage increases.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

    • The brake switch is detected as closed.
    • The master cylinder pressure is detected as being above 862 kPa (125 psi) for 500 milliseconds.

Action Taken When the DTC Sets

    • The EBCM disables the VSES.
    • The message center displays the SERVICE STABILITY SYSTEM message.

Conditions for Clearing the DTC

    • The conditions for setting the DTC are no longer present (the DTC is not current) and you use the scan tool Clear DTCs function.
    • The current DTC clears when a DTC sets which directly indicates a brake switch or master cylinder pressure sensor malfunction.

Diagnostic Aids

Thoroughly inspect connections or circuitry that may cause an intermittent malfunction. Refer to the following:

    •  Testing for Electrical Intermittents
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs
    •  Connector Repairs

Step

Action

Values

Yes

No

1

Did you perform the ABS Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - ABS

2

Drive the vehicle in order to verify that the brakes do not self-apply during turning maneuvers.

Do the brakes self-apply during turning maneuvers?

--

Go to Symptoms - Hydraulic Brakes

Go to Step 3

3

  1. Install a scan tool.
  2. Turn ON the ignition.
  3. Select the VSES data list on the scan tool.
  4. Observe the Master Cylinder Pressure Sensor Input (psi) on the scan tool.

Is the Master Cylinder Pressure Sensor Input within the specified range?

0-32 psi

Go to Step 4

Go to DTC C0201-C0204

4

Apply and release the brake several times while observing the Brake Switch Status on the scan tool.

Is Brake Switch Status Off with the brake released and On with the brake applied?

--

Go to Diagnostic Aids

Go to DTC C0281 or C081