P1381

Circuit Description
This diagnostic will detect a loss of serial communication from the Electronic Brake Control Module (EBCM) to the Control Module (PCM/VCM). This serial communication is essential to distinguish misfire from a rough road condition.

Conditions for Running the DTC
^ The vehicle speed is more than 1 mph (2 km/h).
^ The engine speed is less than 5,800 RPM.
^ The engine load is less than 89% Engine misfire is detected.

Conditions for Setting the DTC
A serial data malfunction is preventing the VCM from receiving rough road detection data.

Action Taken When the DTC Sets
The Malfunction Indicator Lamp (MIL) will not be illuminated. This DTC is stored as a history DTC.

Conditions for Clearing the MIL/DTC
^ A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles.
^ A warm-up cycle occurs when the coolant temperature has risen 22°C (40°F) from the start-up coolant temperature and the engine coolant temperature exceeds 70°C (160°F) during the same ignition cycle.
^ Use the scan tool Clear Information function.

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 check any circuitry that is suspected of causing the intermittent complaint. Refer to Intermittents and Poor Connections Diagnosis in Symptoms. Intermittent Conditions

Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
2. This step isolates an open serial data circuit from the EBCM system.