Engine Control Module: Description and Operation

The Powertrain Control Module (PCM) detects engine operation, vehicle driving conditions, and exhaust gas oxygen content from various switches, sensors, and other component. The sensors and switches measure:

- Intake air temperature
- Atmospheric pressure
- Coolant temperature
- Engine speed
- Throttle position
- Exhaust gas oxygen content

These sensors and switches detect changes in operating conditions to ensure proper control of the fuel injectors, maintaining optimum exhaust emissions and engine performance throughout the engine's entire operating range.

The PCM determines the basic fuel requirements of the engine from the Volume Air Flow (VAF) sensor.

The PCM also has partial control of:

- Evaporative emission system
- Exhaust gas recirculation system
- Idle Air Control Bypass Air (IAC BPA) valve.
- Electronic spark advance system
- Ignition system
- Deceleration system