Engine Control Module: Description and Operation

Powertrain Control Module (PCM):

The Powertrain Control Module (PCM) performs the following functions:
- accepts information from various engine sensors to compute the required fuel trim necessary to maintain a prescribed air/fuel ratio throughout the entire engine operational range.
- sends out a command to the fuel injectors to meter the appropriate quantity of fuel.
- determines and compensates for the age of the vehicle and its uniqueness.
- automatically senses and compensates for changes in altitude (from sea level to mountains).