GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2003 🢒 GMC MD Steel Tilt (W Model) 🢒 Engine 🢒 Engine Controls - 5.0L and 5.7L 🢒 DTC P1380

Circuit Description

This diagnostic trouble code (DTC) is used to determine when the electronic brake control module (EBCM) has lost the ability to provide rough road data to the control module for misfire detection (DTC P0300). When the powertrain control module (PCM) detects this condition on the Class 2 Serial Data circuit, this DTC will be set.

Conditions for Running the DTC
    • The vehicle speed is at least 2 km/h (1 mph).
    • The engine speed is less than 5800 RPM.
    • The engine load is less than 89 percent.

Conditions for Setting the DTC

The PCM determines that the ABS system is unable to detect a rough road condition.

Action Taken When the DTC Sets
    • The control module stores the DTC information into memory when the diagnostic runs and fails.
    • The malfunction indicator lamp (MIL) will not illuminate.
    • The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
    • The driver information center, if equipped, may display a message.

Conditions for Clearing the DTC
    • A current DTC Last Test Failed clears when the diagnostic runs and passes.
    • A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
    • Clear the DTC with a scan tool.

Diagnostic Aids

Check for the following conditions:

An intermittent may be caused by any of the following conditions:

    • A poor connection
    • Rubbed through wire insulation
    • A broken wire inside the insulation

Thoroughly inspect any circuitry that is suspected of causing the intermittent complaint. Refer to Testing for Intermittent and Poor Connections in Wiring Systems.

If a repair is necessary, refer to Wiring Repairs or Connector Repairs in Wiring Systems.

Test Description

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

  1. This step isolates an open serial data circuit from the EBCM system.

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

1

Did you perform the Diagnostic System Check-Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

  1. Disconnect the PCM and EBCM.
  2. Check the serial data circuit between the PCM and the EBCM for a poor connection.

Did you find a problem?

Go to Step 3

Go to A Diagnostic System Check -- ABS in Antilock Brake System

3

Repair as necessary. Refer to Wiring Repairs and Connector Repairs in Wiring Systems.

Is the action complete?

Go to Step 4

--

4
  1. Using the scan tool, clear the DTCs.
  2. Start the engine.
  3. Allow the engine to idle until the engine reaches normal operating temperature.
  4. Select the DTC, and the specific DTC function.
  5. Enter the DTC number which was set.
  6. Operate the vehicle with the Conditions for Setting this DTC, until the scan tool indicates the diagnostic Ran.

Does the scan tool indicate the diagnostic Passed?

Go to Step 5

Go to Step 2

5

Does the scan tool display any additional undiagnosed DTCs?

Go to Diagnostic Trouble Code (DTC) List

System OK