Electronic Brake Control Module: Description and Operation

The PCM uses the UART serial data line (CKT 800) to communicate with various other components and systems within the vehicle. The PCM receives rough road information from the EBCM on the serial data circuit. The PCM uses the rough road information to enhance the misfire diagnostic by detecting crankshaft speed variations caused by driving on rough road surfaces. This allows false misfire information to be rejected. The EBTCM / EBCM calculates rough road information by monitoring the ABS wheel speed sensors. If a malfunction occurs which does not allow the EBTCM/ EBCM to transmit 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 rough road information while a misfire DTC is requesting the MIL, DTC P1381 will set.