Manifold Absolute Pressure (MAP) Sensor

The MAP sensor is mounted on the right side of the engine compartment or on the air cleaner. This sensor is a variable resistor type which has a vacuum hose connected to the throttle body. The sensor monitors changes in intake manifold pressure which result from engine load and speed changes. As MAP changes, the electrical resistance of the sensor changes. The ECM uses the resistance value of the sensor to control injector pulse width. The MAP sensor also allows for altitude compensation of the air/fuel ratio.