GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The PCM receives rough road information from the EBCM / EBTCM on the Class II 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 / EBTCM transmits rough road information based on inputs from the wheel speed sensors. If the EBCM / EBTCM detects a condition which will not allow it to properly identify rough road situations while a misfire condition is being detected by the PCM, DTC P1380 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 has detected a EBCM / EBTCM 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

Values

Yes

No

1

Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?

--

Go to Diagnostic System Check - ABS

Go to Powertrain On Board Diagnostic (OBD) System Check