Manifold Absolute Pressure (Map) Sensor

The MAP sensor responds to absolute pressure in the intake manifold and sends input voltage to the ECU. As engine load changes, intake manifold pressure changes, causing the MAP sensor resistance to change.

When resistance in the MAP sensor changes, this causes voltage signal to the ECU to change. The change in input voltage allows the ECU to adjust air/fuel ratio as necessary. During engine start-up, the MAP sensor input voltage signal supplies the ECU with ambient barometric pressure.