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.

The voltage signal transmitted during a closed throttle condition would be relatively low compared with a higher voltage signal created 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.