The MAP (Manifold Absolute Pressure) sensor creates pressure through the turbocharger, which changes according to the position of the throttle and the engine speed. The ECM (Engine Control Module) uses this information to help diagnose the BARO (Barometric Pressure) sensor and protect against engine overpressure.
The MAP sensor is composed of a low reference circuit, a signal circuit, and a 5-volt reference circuit. On the other hand, the engine control module gives a 5-volt reference and at the same time distributes ground in a low reference circuit. The MAP sensor sends a signal to the ECM indicating any pressure changes, and the ECM checks this signal as soon as the voltage drops below normal. The ECM compares the value obtained to the actual signal.