Manifold Pressure/Vacuum Sensor: Description and Operation

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

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.

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