Powertrain Control Module (Pcm)
The Powertrain Control Module (PCM) has memory storage and a permanent diagnostic trouble code memory. One PCM is used for all applications worldwide. New PCM must be coded with the V.A.G. 1551 scan tool when installed in vehicle.
The PCM receives signals from Mass Airflow (MAF) sensor, Heated Oxygen Sensor (HO2S), Engine Coolant Temperature (ECT) sensor, Throttle Position (TP) sensor, Closed Throttle Position (CTP) switch, Knock Sensor (KS), Crankshaft Position (CKP) sensor, engine speed (RPM) sensor, Camshaft Position (CMP) sensor and EGR sensor. See Fig 1 . PCM uses data from these sensors to vary air/fuel mixture and ignition timing to maintain optimum performance, fuel economy and emission standards.
NOTE:
Components are grouped into 2 categories: input (sensor) devices and output (actuator) signals. INPUT DEVICES are components that control or produce voltage signals monitored by PCM. OUTPUT SIGNALS are components controlled by PCM.