Manifold Pressure/Vacuum Sensor: Description and Operation

MAP Sensor Circuit:

PURPOSE
The manifold absolute pressure sensor sends a voltage signal to the ECM based manifold pressure (vacuum). The ECM uses this reference to determine engine load.

LOCATION
The sensor is mounted to the right side of the firewall, near the wiper motor.

CONSTRUCTION
The sensor consists of a solid state pressure sensor connected to an external vacuum nipple.


OPERATION
A 5 volt supply is fed to the sensor whenever the ignition is turned on. As pressures (vacuum) are detected, a signal (approx. 1 - 4 volts) is returned to the ECM. The vacuum to signal ratio is constant, making very precise measurement possible.