Manifold Absolute Pressure (Map)

The speed density method is used to compute airflow rate on models equipped with a MAP sensor. Manifold pressure and temperature are used by ECA to calculate airflow rate to ECA. The MAP sensor responds to manifold vacuum changes due to engine load and speed changes.

The MAP sensor also uses frequency to measure manifold vacuum. The MAP sensor is used as a barometric sensor for altitude compensation, updating ECA during Key On, Engine Off (KOEO) and Wide Open Throttle (WOT). By monitoring MAP sensor output voltage, ECA determines correct spark advance, EGR flow and air/fuel ratio. If MAP sensor fails, ECA will supply a fixed MAP value and use Throttle Position Sensor (TPS) to control fuel distribution.