P1381

Engine Controls Schematics: Generator, Brake And Traction Controls, Oil Level And BTSI Switches:

CIRCUIT DESCRIPTION

The Powertrain Control Module (PCM) receives rough road information from the Electronic Brake Traction Control Module (EBTCM) on the Class 2 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 EBTCM transmits rough road information based on inputs from the wheel speed sensors. If a loss of communication occurs which causes the PCM not to receive rough road information while DTC P0300 is requesting the MIL, DTC P1381 will 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 more than 10 mph.
^ A misfire DTC is occurring and requesting Malfunction Indicator Lamp (MIL) illumination.

CONDITIONS FOR SETTING THE DTC
The PCM is detecting a loss of communication with the EBTCM for at least 10 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM will not 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 not 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 can be cleared by using a scan tool.

DIAGNOSTIC AIDS
Check for the following conditions:
^ A faulty connection at the PCM or at the EBTCM- Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connections. Use a corresponding mating terminal to test for proper terminal tension.
^ Inspect the wiring harness for damage. If the harness appears to be OK, observe ABS data on the scan tool while moving connectors and wiring harnesses related to the EBTCM. A loss of ABS data will indicate the location of the malfunction.

Reviewing the Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.


TEST DESCRIPTION

Diagnostic Chart:

The numbers below refer to the step numbers on the diagnostic table.
2. Ensures that the EBTCM is capable of transmitting serial data on the UART serial data circuit.
4. Checks the UART serial data circuit at the EBTCM for the correct voltage.