For 1990-2009 cars

Refer to Engine Controls Schematics .

### Circuit Description

The powertrain control module (PCM) receives rough road information from the electronic brake control module (EBCM) on the 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 EBCM transmits rough road information based on inputs from the wheel speed sensors. If the EBCM detects a condition which does not allow the EBCM to properly identify rough road situations while a misfire condition is being detected by the PCM, DTC P1380 is 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 that the malfunction indicator lamp (MIL) be illuminated.

### Conditions for Setting the DTC

The PCM has detected a EBCM rough road sensing error.

### 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.

#### DTC P1380 - EBCM DTC Detected - Rough Road Data Unusable

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Powertrain ON-Board Diagnostic (OBD) System Check? | -- | Go to Diagnostic System Check - ABS in Antilock Brake System | Go to Powertrain On Board Diagnostic (OBD) System Check