Manifold Pressure/Vacuum Sensor: Description and Operation

MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR

Manifold Absolute Pressure (MAP) Sensor:

The MAP sensor is located in the intake manifold near the Throttle Actuator Control (TAC) module. The MAP sensor is a transducer that varies resistance according to changes in intake manifold pressure (vacuum). The ECM measures the signal voltage from the MAP sensor, which is a reduced value of the ECM 5 volt reference. The voltage ranges from 1.0-1.5 volts at idle (low pressure/high vacuum) to 4.5-4.8 volts at wide open throttle (high pressure/low vacuum).

The MAP sensor is primarily used for fuel control. Low intake manifold pressure indicates low engine RPM or low engine load. The higher the pressure in the intake manifold, the greater the load on the engine. The MAP sensor is also used for ignition timing and EVAP purge solenoid duty cycle.