Manifold Pressure/Vacuum Sensor: Description and Operation

PURPOSE
The MAP sensor detects engine load by sensing intake manifold pressure. The ECM uses the sensor input to provide proper compensation for acceleration and periods of high 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.