Manifold Pressure/Vacuum Sensor: Description and Operation

MAP Sensor:

MAP Sensor Output Characteristics:

MANIFOLD ABSOLUTE PRESSURE SENSOR
The Manifold Absolute Pressure (MAP) sensor measures the change in the intake manifold pressure (vacuum). The MAP sensor consists of a semi-conductor type pressure converting element, which converts a pressure change into an electrical change, and an electronic circuit which amplifies and corrects the electrical change. Refer to the accompanying image for a voltage output chart.

OPERATION
The Engine Control Module (ECM) applies 5 volts to the MAP sensor. The change in the pressure, that results from the engine load and rpm changes, is converted into a voltage input that is monitored by the ECM. A low voltage reading at the ECM indicates low manifold pressure, and a high voltage reading at the ECM indicates high manifold pressure.