Powertrain Control Module
WARNING: This page is about a different car, the 2002 Mercury Villager. However, it is still accessible from the selected car via links, so may be relevant.
The PCM has a single 104-pin connector. PCM receives input from sensors and other electronic components such as switches and relays. Based on information received and programmed into its Keep Alive Random Access Memory (RAM), PCM generates output signals to control various relays, solenoids and actuators.
PCM monitors several different engine control system circuits. If a malfunction occurs, PCM will record a Diagnostic Trouble Code (DTC) the next time engine is started and the same malfunction is detected. When a DTC is stored, PCM will also record and store engine operating conditions when malfunction occurred. This information is referred to as freeze frame data. See FREEZE FRAME DATA MODE under ADDITIONAL SYSTEM FUNCTIONS.