Manifold Absolute Pressure (MAP) Sensor

Manifold pressure and temperature are used to calculate the airflow rate to the ECA. The MAP sensor responds to manifold vacuum changes due to engine load and speed changes.

The MAP sensor uses frequency to measures manifold vacuum. The MAP sensor is used as a barometric sensor for altitude compensation, updating the ECA during Key On, Engine Off (KOEO) and at Wide Open Throttle (WOT). By monitoring MAP sensor output voltage, the ECA can determine correct rate of spark advance, EGR flow and air/fuel ratio. If MAP sensor fails, the ECA will supply a fixed MAP value and use the Throttle Position Sensor (TPS) to control fuel distribution. See INPUT DEVICES in this article.