Manifold Absolute Pressure (MAP) Sensor

MAP sensor, mounted on left side of cowl, monitors vacuum in the EGR system. It senses the actual vacuum in the EGR vacuum line and sends a signal to the ECM.

The signal is compared to the EGR duty cycle calculated by the ECM. If there is a minor difference in the vacuum value sensed and the ECM command, the ECM corrects. When a major difference is sensed, the ECM recognizes a fault and sends a full EGR signal.