DTC P1381 Misfire Detected - No Communication with Brake Control Module. Pontiac Grand Prix 2000

For 1990-2009 cars only

Makes 🢒 Pontiac 🢒 2000 🢒 Grand Prix 🢒 Engine 🢒 Engine Controls - 3.8L 🢒 DTC P1381 Misfire Detected - No Communication with Brake Control Module

Refer to Data Link Connector (DLC) Schematics

UART

Data Link Communications Components
Data Link Communications Circuit Description
Class 2
Power/Grounds, and E&C
Handling ESD Sensitive Parts Notice
.

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 CKT 800 of the universal asynchronous receiving and transmitting (UART) serial data circuit. The PCM uses the rough road information in order to enhance the misfire diagnostic by distinguishing the crankshaft speed variations that are caused by driving on rough road surfaces from variations that are caused by true misfires. The EBCM or EBTCM transmits the rough road information based on inputs from the wheel speed sensors. If a loss of communication occurs which causes the PCM to not receive the 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 the MIL to be illuminated.

Conditions for Setting the DTC

The PCM is detecting a loss of communication with the EBCM or EBTCM for at least 5 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

Inspect for the following conditions:

Many situations may lead to an intermittent condition. Perform each inspection or test as directed.

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.

•	Loose terminal connection

-	Use a corresponding mating terminal to test for proper tension. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair.

Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair.

•

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 Wiring Repairs in Wiring Systems for diagnosis and repair.

•	Inspect the powertrain control module (PCM) and the engine grounds for clean and secure connections. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair.

If the condition is determined to be intermittent, reviewing the Snapshot or Freeze Frame/Failure Records may be useful in determining when the DTC or condition was identified.

Test Description

The numbers below refer to the step numbers on the Diagnostic Table.

This step ensures that the EBCM/EBTCM is capable of transmitting the serial data on the UART serial data circuit.

Test the UART serial data circuit at the EBCM/EBTCM for correct voltage.

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

Step	Action	Values	Yes	No
1	Did you perform the Powertrain On Board Diagnostic (OBD) System Check?	--	Go to Step 2	Go to Powertrain On Board Diagnostic (OBD) System Check
2	Turn ON the ignition, with the engine OFF. Attempt to display the ABS data on the scan tool. Is the ABS displayed?	--	Go to Step 3	Go to Step 4
3	Test and inspect the serial data circuit for an open or a poor connection between the PCM and the EBCM. If you find a problem repair the condition as necessary. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition?	--	Go to Step 7	Go to Step 4
4	Turn OFF the ignition. Disconnect the EBCM. Turn ON the ignition, with the engine OFF. Use a DMM in order to measure the voltage on the UART serial data circuit at the EBCM harness connector. Does the voltage vary within the specified values?	1-5V	Go to Step 5	Go to Step 6
5	Inspect for a poor connection at the EBCM. If you find a problem, repair the condition as necessary. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition?	--	Go to Step 7	Go to Step 6
6	Check for an open in the serial data circuit to the EBCM. Refer to UART Data Link Communications Components Data Link Communications Circuit Description Class 2 Power/Grounds, and E&C Handling ESD Sensitive Parts Notice in the data link connector schematics for a complete mechanization. If you find a problem, repair the condition as necessary. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition?	--	Go to Step 7	Go to Diagnostic System Check - ABS in Antilock Brake Systems
7	Turn ON the ignition, with the engine OFF. Attempt to display the ABS data on the scan tool. Is the ABS data displayed?	--	System OK	Go to Step 4