GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2004 🢒 Park Avenue 🢒 Brakes 🢒 Antilock Brake System 🢒 DTC C1237

Circuit Description

The electronic brake control module (EBCM) monitors the voltage level available for system operation. If the voltage level is too high, damage may result in the system. When the EBCM detects a high voltage condition, the EBCM turns OFF the system relay which removes battery voltage from the solenoid valves and pump motor.

Conditions for Running the DTC

The vehicle speed is greater than 8 km/h (5 mph).

Conditions for Setting the DTC

The system voltage is greater than 16.4 volts for 0.72 seconds.

Action Taken When the DTC Sets

If equipped, the following actions occur:

    • The EBCM disables the DRP/ABS/TCS/VSES for the duration of the ignition cycle.
    • The ABS indicator turns ON.
    • The Traction Off indicator turns ON.
    • The DIC displays the Service Stability System message.
    • The EBCM will also set DTC C1248.
    • The red Brake warning indicator turns ON.

Conditions for Clearing the DTC
    • The condition for the DTC is no longer present and the DTC is cleared with a scan tool.
    • The electronic brake control module (EBCM) automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

Diagnostic Aids

A possible cause of this DTC is overcharging.

Test Description

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

  1. Use the scan tool in order to inspect the voltage to the EBCM.

    2.

  2. Use the scan tool in order to inspect the voltage to the body control module (SBM). A high voltage value in multiple modules indicates a concern in the charging system.

    3.

  3. Verifies that the condition is still present.

Step

Action

Values

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. 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 Switched System Battery Voltage parameter in the DRP/ABS/TCS data list.

Does the scan tool indicate that the voltage is greater than the specified value?

16.4 V

Go to Step 3

Go to Diagnostic Aids

3

With a scan tool, observe the Battery Voltage parameter in the Body Control Module data list.

Does the scan tool indicate the voltage is greater than the specified value?

16.4 V

Go to Diagnostic System Check - Engine Electrical in Engine Electrical

Go to Step 4

4

  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 test.

Does the DTC reset?

--

Go to Step 5

Go to Diagnostic Aids

5

Important: Perform the setup procedure for the EBCM. An unprogrammed EBCM will result in the following conditions:

   • Inoperative or poorly functioning system operations
   • The EBCM sets DTC C1248 and DTC C1255m3.

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

Did you complete the repair?

--

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 test.

Does the DTC reset?

--

Go to Step 2

System OK