Circuit Description
The PCM receives rough road information from the EBCM / EBTCM on the Class 2 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 be set.
Conditions for Running the DTC
| • | Engine load is less than 87 percent. |
| • | Engine speed is less than 5000 RPM. |
| • | Vehicle speed is greater 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 powertrain control module (PCM) stores the DTC information into memory when the diagnostic runs and fails. |
| • | The malfunction indicator lamp (MIL) will not illuminate. |
| • | The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | A History DTC will clear after forty consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic. |
| • | A last test failed (Current DTC) will clear when the diagnostic runs and does not fail. |
| • | Use a scan tool in order to clear the MIL/DTC. |
| • | Interrupting the PCM battery voltage may or may not clear DTCs. This practice is not recommended. Refer to Powertrain Control Module Description , Clearing Diagnostic Trouble Codes. |
Diagnostic Aids
DTC P1380 set indicates that the ABS / TCS system has detected a malfunction which will not allow the EBCM / EBTCM to transmit correct rough road data to the PCM. The Diagnostic System Check - ABS in Anti-Locking System -- Delco VI or Diagnostic System Check - ABS in Anti-Locking System -- Bosch 5.3 should be used to diagnose this condition.
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 Delco VI or Diagnostic System Check - ABS in Antilock Brake System Bosch 5.3 |
