The Powertrain Control Module (PCM) performs many functions on your vehicle. The module accepts information from various engine sensors and computes the required fuel flow rate necessary to maintain the correct amount of air/fuel ratio throughout the entire engine operational range.
The PCM controls the following items:
The PCM constantly looks at the information from various sensors, and controls the systems that affect vehicle performance. The PCM also performs the diagnostic function of the system. It can recognize operational problems, alert the driver through the Malfunction Indicator Light (MIL) or SERVICE ENGINE SOON light, and store diagnostic trouble codes which identify the problem areas to aid in making repairs.
The PCM supplies either 5.0 or 12.0 volts to power various sensors or switches. This is done through resistances in the PCM which are so high in value that even a test light will not light when connected to the circuit. In some cases, even an ordinary DMM will not give an accurate reading because it's resistance is too low. A DMM with at least 10 megaohms input impedance is required to ensure accurate voltage readings.
The PCM controls output circuit devices such as fuel injectors, idle air control, cooling fan relays, etc. by controlling the ground or power feed circuit through transistors or a device called a "Driver".
REMOVAL & INSTALLATION
- Disconnect the negative battery cable.
- Remove the left sound insulator below the steering wheel.
- Loosen the 2 PCM electrical connector's screws.
- Detach the PCM electrical connectors and move them out of the way.
- Open the PCM bracket latch.
- Remove the PCM from the bracket.
- Slide the PCM into the PCM bracket until retainer locks the PCM into position.
- Close the PCM bracket latch.
- Attach the PCM electrical connectors.
- Tighten the connector screws to 71 inch lbs. (8 Nm).
- Install the sound insulator.
- Connect the negative battery cable.