Originally posted by dole21@May 22 2005, 09:33 PM
P1380 described as "ABS Rough road/Misfire Diag. Prevented 
CIRCUIT DESCRIPTION
The PCM receives rough road information from the EBCM/EBTCM on the UART serial data circuit (CKT 800). 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
* 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 PCM will not illuminate the Malfunction Indicator Lamp (MIL).
* The PCM will store conditions which were present when the DTC set as Failure Records data only. This information will not be stored as Freeze Frame data.
CONDITIONS FOR CLEARING THE MIL/DTC
* A History DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
* The DTC can be cleared by using a scan tool.
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 ABS/TCS Functional Test in ABS/TCS Diagnosis should be used to diagnose this condition.
IMPORTANT: Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.
* Poor terminal connection. Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Use a corresponding mating terminal to test for proper tension. Refer to Diagrams for diagnosis and repair.
* Damaged harness. Inspect the wiring harness for damage. If the harness inspection does not reveal a problem, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the scan tool display may indicate the location of the fault. Refer to Diagrams for diagnosis and repair.
* Inspect the PCM and the engine grounds for clean and secure connections.
If the DTC is determined to be intermittent, reviewing the Failure Records can be useful in determining when the DTC was last set.
h34r:
