GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Oldsmobile 🢒 2001 🢒 Aurora 🢒 Engine 🢒 Engine Controls - 3.5L 🢒 DTC P1381

Circuit Description

The powertrain control module (PCM) receives rough road information from the electronic brake control module (EBCM) or the electronic brake and 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 EBCM or 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 malfunction indicator lamp (MIL), DTC P1381 will set.

Conditions for Running the DTC
    • The engine load is less than 87 percent.
    • The engine speed is less than 5,000 RPM.
    • The vehicle speed is more than 10 mph.
    • A misfire DTC is occurring, and is requesting the MIL to be illuminated.

Conditions for Setting the DTC

The PCM detects a loss of communication with the EBCM or EBTCM for at least 10 seconds.

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

Notice: Use the connector test adapter kit J 35616-A for any test that requires probing the following items:

   • The PCM harness connectors
   • The electrical center fuse/relay cavities
   • The component terminals
   • The component harness connector
Using this kit will prevent damage caused by the improper probing of connector terminals.

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

If the problem is intermittent, refer to Intermittent Conditions .

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step ensures that the EBCM and/or EBTCM is capable of transmitting serial data.

Step

Action

Yes

No

1

Did you perform the Diagnostic System Check-Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

  1. Select Chassis Diagnostics on the scan tool.
  2. Attempt to display the antilock brake system (ABS) data on the scan tool.

Can ABS data be displayed?

Go to Step 3

Go to Diagnostic Starting Point - Antilock Brake System in Antilock Brake System

3
  1. Check the serial data circuit for an open or a poor connection between the PCM and the EBTCM.
  2. If a problem is found, repair as necessary. Refer to Diagnostic Starting Point - Data Link Communications in Data Link Communications.

Was a problem found?

System OK

Go to Diagnostic Aids