Manifold Absolute Pressure Sensor

Manifold Absolute Pressure (MAP) sensor is connected to ECM 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 ECM varies. ECM 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.