Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptors
DTC P1380: Misfire Detected - Rough Road Data Not AvailableDTC P1381: Misfire Detected - No Communication With Brake Control Module
Circuit/System Description
The engine control module (ECM) identifies engine misfire by detecting variations in crankshaft speed. Crankshaft speed variations can also occur when a vehicle is operated over a rough road. The antilock brake system (ABS) can detect if the vehicle is on a rough surface based on wheel acceleration/deceleration data supplied by each wheel speed sensor. This information is sent to the ECM by the electronic brake control module (EBCM) through pulse width modulation (PWM) serial data line. The ECM then uses this information to determine if the crankshaft variations are being caused by an actual engine misfire or from being driven on a rough surface.
If the ABS is found to be malfunctioning, the ECM will still continue to detect for misfire. However, if a misfire DTC is set, this additional DTC will also be set, indicating that rough surface data was not usable during the misfire detection due to the ABS malfunction.
Conditions for Running the DTC
| • | Engine run time is greater than 10 seconds. |
| • | The DTCs run once the above condition is met. |
Conditions for Setting the DTC
The ECM does not receive rough road detection data from the EBCM for more than 2 seconds.
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
Circuit/System Testing
Ignition ON, observe the DTC information with a scan tool.
| ⇒ | If DTCs P1380 or P1381 failed this ignition, refer to No Communication with Electronic Brake Control Module . |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for engine control module replacement, setup, and programming
