Manifold Pressure/Vacuum Sensor: Description and Operation

The MAP sensor supplies a varying DC voltage signal to the ECM representing manifold pressure----usually used in conjunction with a BARO sensor.
- When manifold pressure is low (high vacuum), sensor output voltage is low--under 1 volt.
- When manifold pressure is high (low vacuum), sensor output voltage is high--4.5 volts.

NOTE: Turbocharged models are equipped with a MAP sensor with internal altitude compensation.