Powertrain Control Module (Pcm)

PCM is a digital computer that controls ignition timing, air/fuel ratio, emission control devices, cooling fan, charging system, idle speed, fuel pump and tachometer. The control unit is located in the engine compartment. PCM uses data from various input sources to control output devices in order to achieve optimum engine performance for all operating conditions.

PCM has voltage converters that convert battery voltage to regulated 5-volt and 8-volt outputs. The 8-volt output powers the distributor pick-up and crankshaft position sensor. The 5-volt output powers coolant temperature, charge temperature, fuel temperature, manifold absolute pressure and throttle position sensors.