GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The electronic brake control module (EBCM) sends a engine drag control (EDC) request via a dedicated data line. The powertrain control module (PCM) supplies a pull up voltage of 5 volts that the EBCM switches to ground to create the signal.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC C0243 Engine Drag Control

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

The EBCM receives a serial data message from the PCM indicating that the EDC circuit has failed.

Action Taken When the DTC Sets

    • The EBCM disables the EDC for the duration of the ignition cycle.
    • The driver information center (DIC) displays the Service Stability System message.
    • The Antilock Brake System (ABS)/Traction Control System (TCS) remains functional.

Conditions for Clearing the DTC

    • The condition for the DTC is no longer present and the DTC is cleared with a scan tool.
    • The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

Diagnostic Aids

The following conditions can cause this concern:

    • An open in the EDC control circuit.
    • An short to ground or voltage in the EDC control circuit.
    • A wiring problem, terminal corrosion, or poor connection in the EDC control circuit.

Test Description

The number below refers to the step number on the diagnostic table.

  1. This vehicle is equipped with a ECM which uses an electrically erasable programmable read only memory (EEPROM). When replacing the ECM, the replacement ECM must be programmed.

Step

Action

Values

Yes

No

Schematic Reference: Antilock Brake System Schematics

Connector End View Reference: Antilock Brake System Connector End Views , Engine Control Module Connector End Views for the 6.0L engine, or Engine Controls Connector End Views for the 3.6L engine

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Inspect the electronic brake control module (EBCM) ground and engine control module (ECM) ground, making sure each ground is clean and torqued to the proper specification. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 10

Go to Step 3

3

  1. Disconnect the EBCM harness connector.
  2. Install the J 39700 Universal Pinout Box using the J 39700-300 Cable Adapter to the EBCM harness connector and the EBCM connector.
  3. Disconnect the ECM harness connector.
  4. Turn ON the ignition, with the engine OFF.
  5. Measure the voltage from the engine drag control signal circuit to a good ground.

Does the voltage measure near the specified value?

B+

Go to Step 4

Go to Step 5

4

  1. Turn OFF the ignition.
  2. Disconnect the J 39700-300 from the EBCM connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Test the engine drag control signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 10

Go to Step 6

5

  1. Turn OFF the ignition.
  2. Disconnect the J 39700-300 from the EBCM connector.
  3. Test the engine drag control signal circuit for the following conditions:
  4. • An open
    • A short to ground
    • A high resistance

Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 10

Go to Step 7

6

Inspect for poor connections the harness connector of the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 10

Go to Step 8

7

Inspect for poor connections the harness connector of the EBCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 10

Go to Step 9

8

Replace the ECM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

--

Go to Step 10

--

9

Replace the EBCM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

--

Go to Step 10

--

10

  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