Manifold Absolute Pressure Sensor (MAP)

On FWD DeVille and Fleetwood, the MAP sensor is located on the right rear side of engine compartment. On all other models, the MAP sensor is located in engine compartment mounted on bracket at end of manifold cover. A hose from the throttle body to the MAP sensor provides a vacuum signal. The sensor monitors changes in intake manifold pressure which result from engine load and speed variations.

When intake manifold pressure increases, additional fuel is required. MAP sends this information to ECM so that the pulse width is increased (time injector is open). As manifold pressure decreases, pulse width is shortened.