What Is PCM (Powertrain Control Module)?

The combined engine and transmission control computer. In many vehicles, the PCM integrates both ECM and TCM functions into a single module.

The PCM manages both engine operation and automatic transmission shifting. It processes inputs from dozens of sensors and controls outputs including fuel injectors, ignition coils, idle air control, transmission solenoids, and more. PCM failures or communication issues can trigger a wide range of P-codes and U-codes.