P1380

DTC P1380 or P1381

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.

* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provide an overview of each diagnostic category.

DTC Descriptors

DTC P1380

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Misfire Detected - Rough Road Data Not Available

DTC P1381

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Misfire Detected - No Communication with Brake Control Module

System Description

The engine control module (ECM) detects engine misfire by detecting variations in crankshaft deceleration between firing strokes. For accurate detection of engine misfire, the ECM must distinguish between crankshaft deceleration caused by actual misfire and deceleration caused by rough road conditions. The antilock brake system (ABS) can detect if the vehicle is on a rough road based on wheel acceleration/deceleration data supplied by the wheel speed sensors. If the ABS detects rough road above predetermined threshold, this information is sent to the ECM. The ECM uses the rough road information when calculating engine misfire. If the ABS is malfunctioning and cannot detect rough roads, the misfire diagnostic will continue to run; however, if an engine misfire DTC sets, this DTC also sets indicating that rough road data was not available, or there was no communication with the brake control module during the misfire calculation due to an ABS malfunction.

Conditions for Running the DTC

* The vehicle speed is greater than 8 km/h (5 mph).

* The engine speed is less than 8,192 RPM.

* The engine load is less than 60 percent.

* Engine misfire is detected and DTC P0300 sets with the MIL illuminated.

* DTCs P1380 and P1381 run continuously when the above conditions are met.

Conditions for Setting the DTC

P1380

* The electronic brake control module (EBCM) sends a message to the ECM indicating that a failure has occurred in the EBCM.

* Engine misfire is detected and DTC P0300 sets with the MIL illuminated.

P1381

* An EBCM malfunction exists for greater than 10 s, preventing the ECM from receiving rough road detection data.

* Engine misfire is detected and DTC P0300 sets with the MIL illuminated.

Action Taken When the DTC Sets

DTCs P1380 and P1381 are Type C DTCs.

Conditions for Clearing the DTC

DTCs P1380 and P1381 are Type C DTCs.

Reference Information

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References Control Module References for scan tool information

Circuit/System Verification

1. Ignition ON, observe the DTC information with a scan tool. DTC UXXXX should not be set.

• If a DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis.

2. Engine idling, observe the EBCM DTC information with a scan tool. EBCM DTCs should not set.

• If a DTC sets, refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis.

• If there are no EBCM DTCs set, refer to the following:

* Symptoms - Antilock Brake System Symptoms - Antilock Brake System for the ABS - Hybrid

* Symptoms - Antilock Brake System Non-Hybrid Less than 3900 kg (8600 lb) GVW for the ABS - Non-Hybrid Less than 3900 kg (8600 lb) GVW

* Symptoms - Antilock Brake System Non-Hybrid Greater than/Equal to 3900 kg (8600 lb) GVW for the ABS - Non-Hybrid Greater than/Equal to 3900 kg (8600 lb) GVW

3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.