Thread: P1380-Misfire Detected-Rough Road data not available

Electronic Brake and Traction Control Module (EBTCM) / Electronic
Brake Control Module (EBCM) - PCM UART Serial Data
The PCM uses the universal asynchronous receiving and transmitting
(UART) serial data line in order to communicate with other components
and systems within the vehicle. If the PCM does not receive the data
from the Electronic Brake and Traction Control Module (EBTCM), or from
the Electronic Brake Control Module (EBCM), the PCM will store DTC
P1573, indicating the loss of communication with the ABS/TCS system.

The PCM also receives rough road information from the EBTCM/ EBCM on
the Class 2 serial data circuit. The PCM uses the rough road
information in order to enhance the misfire diagnostic by detecting
the crankshaft speed variations that are caused by driving on rough
road surfaces. This allows false misfire information to be rejected.
The EBTCM/EBCM calculates the rough road information by monitoring the
ABS wheel speed sensors. If a malfunction occurs which does not allow
the EBTCM/EBCM to transmit the correct rough road information to the
PCM while a misfire DTC is requesting the MIL, DTC P1380 will set. If
a loss of communications occurs which causes the PCM to not receive
the rough road information while a misfire DTC is requesting the MIL,
DTC P1381 will set.

During certain conditions, the PCM can request the EBTCM to shut OFF,
the traction control via the serial data. The following DTCs will
cause traction control to be disabled, cause an ABS/TCS DTC to be set,
and cause the Traction OFF lamp to illuminate: