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OPERATION POWERTRAIN CONTROL MODULE (PCM) The PCM is a pre-programmed, microprocessor digital computer. It regulates ignition timing, air-fuel ratio, emission The PCM receives input signals from various switches and sensors. Based on these inputs, the PCM regulates The PCM adjusts ignition timing based upon inputs it receives from sensors that react to: engine rpm, manifold The PCM adjusts idle speed based on inputs it receives from sensors that react to: throttle position, vehicle speed, Based on inputs that it receives, the PCM adjusts ignition coil dwell. The PCM also adjusts the generator charge NOTE: PCM Inputs: • Accelerator pedal position sensor (if equipped) • A/C request (if equipped with factory A/C) • A/C select (if equipped with factory A/C) • Auto shutdown (ASD) sense • Battery temperature • Battery voltage • Brake switch • CAN bus (+) circuits • CAN bus (-) circuits • Camshaft position sensor signal • Clutch Interlock Switch (if equipped) • Crankshaft position sensor • Data link connection for diagnostic scan tool • EGR position sensor (if equipped) • Engine coolant temperature sensor • Fuel level • Generator (battery voltage) output • Ignition circuit sense (ignition switch in on/off/crank/run position) • Intake manifold air temperature sensor • Knock sensor(s) (if equipped) • Leak detection pump (switch) sense (if equipped) • Manifold absolute pressure (MAP) sensor • Oil pressure sensor • Output shaft speed sensor • Overdrive/override switch • Oxygen sensors • Park/neutral switch (auto. trans. only) • Power ground • Power steering pressure switch (if equipped) • Sensor return • Signal ground 8E - 274 ELECTRONIC CONTROL MODULES - SERVICE INFORMATION WK |