P1381

CIRCUIT DESCRIPTION
This diagnostic will detect a loss of serial communication from the Electronic Brake Control Module (EBCM) to the control module. This serial communication is essential in order to distinguish misfire from a rough road condition.

CONDITIONS FOR RUNNING THE DTC
^ The vehicle speed is 2 km/h (1 mph).
^ The engine speed is less than 5,800 RPM.
^ The engine load is less than 89 percent.
^ Engine misfire is detected.

CONDITIONS FOR SETTING THE DTC
A serial data malfunction is preventing the Powertrain Control Module (PCM) from receiving rough road detection data.

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.
^ Use a scan tool in order to clear the DTC.

DIAGNOSTIC AIDS
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 Diagrams.

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

TEST DESCRIPTION

Steps 1-6:

The number below refers to the step number on the diagnostic table.
3. This step isolates an open serial data circuit from the EBCM system.