Manifold Pressure/Vacuum Sensor: Description and Operation

The manifold absolute pressure (MAP) sensor responds to changes in intake manifold pressure (vacuum).The MAP sensor signal voltage to the PCM varies from below 2 volts at idle (high vacuum) to above 4 volts with the ignition ON, engine not running or at wide-open throttle (low vacuum).
The MAP sensor is used to determine the following:
- Manifold pressure changes while the linear EGR flow test diagnostic is being run. Refer to DTC P0401.
- Barometric pressure (BARO).

If the PCM detects a voltage that is lower than the possible range of the MAP sensor, DTC P0107 will be set.A signal voltage higher than the possible range of the sensor will set DTC P0108.An intermittent low or high voltage will set DTC P1107, respectively.The PCM can detect a shifted MAP sensor. The PCM compares the MAP sensor signal to a calculated MAP based on throttle position and various engine load factors.If the PCM detects a MAP signal that varies excessively above or below the calculated value, DTC P0106 will set.