DTC P1381: Misfire Detected - No Communication With Brake Control Module: Description

Rough roads cause torque on the tires that is transmitted to the powertrain. This condition slows down the crankshaft, giving the appearance of a misfire. Electronic Brake and Traction Control Module (EBTCM) determines rough road surfaces using input from wheel speed sensors. EBTCM then sends rough road data to the Powertrain Control Module (PCM) via class 2 serial data. PCM uses rough road data to enhance misfire diagnostics. This data allows PCM to distinguish crankshaft speed variations caused by rough road surfaces from variations caused by true misfires. If a loss of communication occurs that causes PCM not to receive rough road information when a misfire condition is requesting Malfunction Indicator Light (MIL) on, Diagnostic Trouble Code (DTC) P1381 will set.