GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2003 🢒 Vibe - AWD 🢒 Brakes 🢒 Antilock Brake System 🢒 DTC C1241

Circuit Description

The electronic brake control module (EBCM) monitors the ignition positive voltage level available for antilock brake system (ABS) operation.

Conditions for Running the DTC

The vehicle speed is greater than 3 km/h (2 mph).

Conditions for Setting the DTC
    • The ignition positive voltage is less than 8.5 volts for 10 seconds.
    • The battery positive voltage is greater than 19.0 volts for 1 second.

Action Taken When the DTC Sets
    • The ABS is disabled.
    • 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:

    • Low battery voltage
    • High battery voltage
    • An open or high resistance in the ignition positive voltage circuit
    • An open or high resistance in the motor or solenoid ground circuits
    • 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.

    2.

  2. This step tests the ignition positive voltage supply circuit.

    3.

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

    4.

  4. This step tests the ignition positive voltage circuit.

    5.

  5. This step tests the module ground circuit.

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?

--

Go to Step 2

Go to Diagnostic System Check - ABS

2

  1. Turn OFF all of the accessories.
  2. Install a scan tool.
  3. Start the engine.
  4. Run the engine at approximately 2000 RPM.
  5. With a scan tool, observe the Ignition Voltage parameter in the ABS data list.

Does the scan tool indicate that the ignition voltage is within the specified voltage?

High

Go to Step 3

Go to Step 4

3

  1. Turn OFF the ignition.
  2. Disconnect the EBCM harness connector.
  3. Start the engine.
  4. Run the engine at approximately 2000 RPM.
  5. Measure the voltage between the ignition positive voltage circuit of the EBCM and a good ground.

Does the voltage measure less than the specified value?

17 V

Go to Step 12

Go to Symptoms - Engine Electrical in Engine Electrical

4

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

Does the scan tool indicate the ignition voltage is within the specified range?

Normal

Go to Diagnostic Aids

Go to Step 5

5

  1. Turn OFF the ignition.
  2. Disconnect the EBCM harness connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage between the ignition positive voltage circuit of the EBCM and a good ground.

Does the voltage measure within the specified range?

Battery Voltage

Go to Step 6

Go to Step 7

6

Measure the voltage between the ignition positive voltage circuit and the module ground circuit of the EBCM.

Does the voltage measure within the specified range?

Battery Voltage

Go to Step 11

Go to Step 8

7

Test the ignition positive voltage circuit 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 13

Go to Step 10

8

Test the motor and solenoid ground circuits of the EBCM for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 9

9

Inspect for poor connections or corrosion at the ground G102. 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 13

Go to Step 10

10

Inspect for poor connections at the battery terminals. 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 13

Go to Step 11

11

Inspect for poor connections at the harness connector of the EBCM. 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 13

Go to Step 12

12

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

Did you complete the replacement?

--

Go to Step 13

--

13
  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