What does the manifold absolute pressure (MAP) sensor do?

The manifold absolute pressure (MAP) sensor plays a crucial role in the engine management system by measuring the absolute pressure within the intake manifold. This measurement is vital because it reflects the engine's load conditions. When the engine is under load, such as during acceleration or climbing a hill, the pressure in the manifold decreases, and the MAP sensor detects this change. The sensor then sends a voltage signal to the engine control unit (ECU), which interprets these readings to adjust the fuel injection and ignition timing accordingly to optimize performance and efficiency.

By accurately reading the intake air pressure, the MAP sensor enables the ECU to make real-time adjustments to the air-fuel mixture, thus ensuring the engine operates efficiently under varying conditions. This ability to gauge engine load is essential for maintaining ideal combustion, reducing emissions, and enhancing fuel economy.

Other choices can involve sensors or components with different functions, such as air temperature measurement or exhaust analysis, which do not pertain to the MAP sensor's primary function. Thus, the provided answer aligns perfectly with the MAP sensor’s role in the engine system.