GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2005 🢒 Vibe - FWD 🢒 Restraints 🢒 SIR 🢒 DTC C1203

Circuit Description

The electronic brake control module (EBCM) monitors the powertrain control module (PCM). The EBCM will prevent traction control and vehicle stability control (VSC) operation if it determines fault within the powertrain control system.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC C1203 Throttle Control System

Conditions for Running the DTC

DTC C1203 can be set anytime the ignition is in the ON position.

Conditions for Setting the DTC

The EBCM detects a fault within the PCM data circuits to the EBCM.

Action Taken When the DTC Sets
    • The traction control and VSC is disabled.
    • The VSC 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 circuit in the TRC - high or TRC - low circuits to the EBCM
    • An open or short circuit in the ENG - high or ENG - low circuits to the EBCM
    • An internal EBCM malfunction

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

Test Description

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

  1. This step tests the PCM TRC - high and TRC - low circuits to the EBCM for an open, high resistance, or short.

    2.

  2. This step tests the PCM ENG - high and ENG - low circuits to the EBCM for an open, high resistance, or short.

    3.

  3. Test the PCM ground circuits for an open or high resistance.

Step

Action

Yes

No

Schematic Reference: Antilock Brake System Schematics

Connector End View Reference: Antilock Brake System Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Test the powertrain control module (PCM) TRC - high and TRC - low circuits to the electronic brake control module (EBCM) for an open, high resistance, or short. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 6

Go to Step 3

3

Test the PCM ENG - high and ENG - low circuits to the EBCM for the following:

    • An open
    • High resistance
    • Short to ground

Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 6

Go to Step 4

4

Test the PCM ground circuits for an open or high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 6

Go to Step 5

5

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

Did you complete the replacement?

Go to Step 6

--

6
  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