The MAP sensor (Manifold Absolute Pressure Sensor) measures the absolute pressure in an engine's intake manifold. This information is critical for the engine control unit to inject the correct amount of fuel and adjust the ignition timing. The MAP sensor works closely with other sensors, such as the mass air flow sensor and the throttle position sensor, to ensure efficient engine operation. A faulty MAP sensor can lead to poor starting, increased fuel consumption, or a loss of power.