GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2000 🢒 Bonneville 🢒 DTC 🢒 DTC P1381 Misfire Detected - No Communication with Brake Control Module

Refer to Antilock Brake System Schematic Antilock Brake System Schematics .

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 stores conditions which were present when the DTC set as Failure Records only. This information will not be stored as Freeze Frame Records.

Conditions for Clearing the MIL/DTC
    • The DTC becomes history when the conditions for setting the DTC are no longer present.
    • The history DTC clears after 40 malfunction free warm-up cycles.
    • The PCM receives a clear code command from the 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

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

  1. Ensures that the EBTCM is capable of transmitting serial data on the UART serial data circuit.

    2.

  2. Checks the UART serial data circuit at the EBTCM for the correct voltage.

DTC P1381 - Misfire Detected - No EBCM/PCM Serial Data

Step

Action

Values

Yes

No

1

Was the Powertrain On Board Diagnostic (OBD) System Check performed?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

  1. Turn ON the ignition switch.
  2. Select chassis application on the scan tool.
  3. Attempt to display the ABS data on the scan tool.

Can the ABS data be displayed?

--

Go to Step 3

Go to Step 4

3
  1. Check the serial data circuit for an open or a faulty connection between the PCM and the EBTCM.
  2. If a problem is found, repair as necessary. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems .

Was a problem found?

--

System OK

Go to Diagnostic Aids

4

  1. Turn OFF the ignition switch.
  2. Disconnect the EBCM.
  3. Turn ON the ignition switch.
  4. Use a digital multimeter in order to measure the voltage on the serial data circuit at the EBTCM harness connector.

Does the voltage vary within the specified range?

1-5 V

Go to Step 5

Go to Step 6

5
  1. Check for a faulty connection at the EBTCM.
  2. If a problem is found, replace any terminals as necessary. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems .

Was a problem found?

--

Go to Step 7

Go to Step 6

6
  1. Check for an open in the serial data circuit to the EBCM.
  2. If a problem is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems .

Was a problem found?

--

Go to Step 7

Go to Diagnostic System Check - ABS in Antilock Brake Systems

7
  1. Turn ON the ignition switch.
  2. Select chassis application on the scan tool.
  3. Attempt to display the ABS data on the scan tool.

Can the ABS data be displayed?

--

System OK

Go to Step 4