Manifold Pressure/Vacuum Sensor: Description and Operation

PURPOSE

The vacuum sensor measures intake manifold vacuum. The ECU uses this information to determine engine load.

LOCATION

The sensor is mounted to the center of the firewall, in the engine compartment.

CONSTRUCTION

The sensor contains a silicon diaphragm covering a small vacuum port. When vacuum is applied, the diaphragm flexes which causes a low voltage signal to be generated. An internal circuit amplifies the signal to produce a higher voltage back to the ECU.

OPERATION

Whenever the ignition is on, the sensor produces a readable voltage. The voltage varies dependant upon the amount of vacuum present at the sensing port.