Manifold Absolute Pressure (MAP) Sensor

MAP sensor is connected to PCM by a 3-wire harness and to engine by a manifold vacuum hose. MAP sensor has an internal mechanical resistor which varies resistance based on changes in engine load (manifold vacuum). As internal resistance varies, return voltage signal to PCM varies. PCM interprets this voltage change as changes in engine load and uses this signal to help determine control of fuel injectors and other various sensors and switches.