P1381

Diagnostic Chart:

Refer to Engine control schematics. Electrical Diagrams

CIRCUIT DESCRIPTION
The Powertrain Control Module (PCM) receives rough road information from the Electronic Brake Control Module (EBCM) on the Class II serial data circuit. The PCM uses the rough road information to enhance the misfire diagnostic by distinguishing crankshaft speed variations caused by driving on rough road surfaces from variations caused by true misfires. The EBCM transmits rough road information based on inputs from the wheel speed sensors. If a loss of communication occurs which causes the PCM to not receive rough road information while DTC P0300 is requesting the malfunction indicator lamp (MIL) DTC P1381 is set.

CONDITIONS FOR RUNNING THE DTC
- The engine load is less than 87 percent.
- The engine speed is less than 5000 RPM.
- The vehicle speed is greater than 10 mph.
- A misfire DTC is occurring and requesting that the MIL be illuminated.

CONDITIONS FOR SETTING THE DTC
The PCM detects a loss of communication with the EBCM for at least 5 seconds.

ACTION TAKEN WHEN THE DTC SETS
- The PCM will riot illuminate the Malfunction Indicator Lamp (MIL).
- The PCM will store conditions which were present when the DTC set as Failure Records data only. This information will riot be stored as Freeze Frame data.

CONDITIONS FOR CLEARING THE MIL/DTC
- A History DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction
- The DTC car be cleared by using a scan tool.

DIAGNOSTIC AIDS
Inspect for the following conditions:

IMPORTANT: Remove any debris from the connector surfaces before servicing a component. inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.

- Poor terminal connection-Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Use a corresponding mating terminal to test for proper tension. Refer to Diagrams.
- Damaged harness-Inspect the wiring harness for damage. If the harness inspection does not reveal a problem, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the scan tool display may indicate the location of the fault. Refer to Diagrams.
- PCM and engine grounds for clean and secure connections

If the DTC is determined to be intermittent, reviewing the Failure Records can be useful in determining when the DTC was last set.

TEST DESCRIPTION
Numbers below refer to the step numbers on the Diagnostic Table:
2. Ensures that the EBCM/EBTCM is capable of transmitting serial data on the serial data circuit.