Manifold Pressure/Vacuum Sensor: Description and Operation

MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR-PCM INPUT

Intake Air Temperature Sensor and MAP Sensor-2.0L:

Intake Air Temperature Sensor and MAP Sensor-2.4L:

Intake Air Temperature Sensor and MAP Sensor-2.5L:

The MAP sensor mounts to the intake manifold.

The PCM supplies 5 volts direct current to the MAP sensor. The MAP sensor converts intake manifold pressure into voltage. The PCM monitors the MAP sensor output voltage. As vacuum increases, MAP sensor voltage decreases proportionately. Also, as vacuum decreases, MAP sensor voltage increases proportionately.

At key on, before the engine is started, the PCM determines atmospheric air pressure from the MAP sensor voltage. While the engine operates, the PCM determines intake manifold pressure from the MAP sensor voltage. Based on MAP sensor voltage and inputs from other sensors, the PCM adjusts spark advance and the air/fuel mixture.