Manifold Pressure/Vacuum Sensor: Description and Operation

Manifold Absolute Pressure Sensor (MAP Sensor)
This sensor senses pressure change in the intake manifold and converts it into voltage change. It consists of a semi-conductor type pressure converting element which converts a pressure change into an electrical change and an integrated circuit which amplifies and corrects the electric change.

The ECM (PCM) sends a 5-volt reference voltage to the pressure sensor. As the manifold pressure changes, the electrical resistance of the sensor also changes.

By monitoring the sensor output voltage, ECM (PCM) knows the manifold pressure (intake air volume).

ECM (PCM) uses the voltage signal from the pressure sensor as one of the signals to control various devices.