GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Oldsmobile 🢒 2002 🢒 Bravada - 2WD 🢒 Engine 🢒 Engine Controls - 4.2L 🢒 DTC P1381

Circuit Description

Rough roads cause torque on the tires that is transmitted to the powertrain. This slows down the crankshaft giving the appearance of a misfire. The electronic brake and traction control module (EBTCM) determines rough road surfaces using input from the wheel speed sensors. The EBTCM then sends the rough road data to the powertrain control module (PCM) via class 2 serial data. The PCM uses the rough road data to enhance the misfire diagnostic. The data allows the PCM to distinguish the crankshaft speed variations caused by rough road surfaces from those caused by true misfires. If a loss of communication occurs that causes the PCM not to receive rough road information while a misfire condition is requesting the malfunction indicator lamp (MIL), DTC P1381 will set.

Conditions for Running the DTC
    • The engine load is less than 60 percent.
    • The engine speed is less than 3,200 RPM.
    • The vehicle speed is more than 16 km/h (10 mph).
    • A misfire DTC is occurring and requesting the MIL to be illuminated.

Conditions for Setting the DTC

The PCM is detecting a loss of communication with the EBTCM for less than 5 seconds.

Action Taken When the DTC Sets
    • The PCM will not illuminate the malfunction indicator lamp (MIL).
    • The PCM will store the conditions present when the DTC set as Failure Records data only.

Conditions for Clearing the MIL/DTC
    • The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
    • The DTC can be cleared by using the scan tool Clear DTC Information function.

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.

If the condition is intermittent, refer to Intermittent Conditions .

Test Description

The number below refers to the step number on the diagnostic table.

  1. Ensures that the EBCM/EBTCM is capable of transmitting serial data on the Class 2 serial data circuit.

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

1

Did you perform the Diagnostic System Check-Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

  1. Turn ON the ignition, with the engine OFF.
  2. Select chassis application on the scan tool.
  3. Attempt to display antilock brake system (ABS) data on the scan tool.

Can ABS data be displayed?

Go to Intermittent Conditions

Go to Diagnostic System Check - ABS in Antilock Brake System