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 2.0 volts at idle (high vacuum) to above 4.0 volts with the key on, engine not running or at wide open throttle (low vacuum).

The MAP sensor is used to determine manifold pressure changes while the linear EGR flow test diagnostic is being run (Refer to DTC P0107 Manifold Absolute Pressure (MAP) Sensor Circuit Low Voltage), to determine engine vacuum level for other diagnostics and to determine barometric pressure (BARO).




If the PCM detects a voltage that is lower than the possible range of the MAP sensor, DTC P0107 Manifold Absolute Pressure (MAP) Sensor Circuit Law Voltage will be set. A signal voltage higher than the possible range of the sensor will set DTC P0108 Manifold Absolute Pressure (MAP) Sensor Circuit High Voltage. An intermittent low or high voltage will set DTC P1107 Manifold Absolute Pressure (MAP) Sensor Circuit Intermittent Low Voltage or DTC P1106 Manifold Absolute Pressure (MAP) Sensor Circuit Intermittent High Voltage respectively. The PCM can also 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