Manifold Absolute Pressure (MAP) Sensor

MAP sensor measures and transmits a varying signal based on manifold pressure. Manifold pressure changes with engine load and RPM. The ECM uses MAP sensor signal to control fuel delivery and ignition timing.

Voltage signal transmitted during closed throttle condition would be relatively low compared to higher voltage signal created during Wide Open Throttle (WOT) full-load condition.

The MAP sensor also measures barometric pressure under certain conditions, allowing the ECM to adjust for altitude changes.