Which sensor's functionality can be checked by measuring the pulse width of the fuel injector?

The functionality of the Mass Air Flow (MAF) sensor can indeed be assessed indirectly by measuring the pulse width of the fuel injector. In an ideal operating condition, the fuel injector pulse width is closely tied to the amount of air entering the engine, which is measured by the MAF sensor.

When the MAF sensor is functioning correctly, it sends a signal to the engine control unit (ECU) that reflects the air flow into the intake manifold. This information is crucial for determining the correct fuel delivery to maintain the optimal air-fuel ratio for combustion. If there's a problem with the MAF sensor, the readings it provides may cause the ECU to adjust the pulse width of the fuel injectors incorrectly, resulting in a rich or lean fuel mixture. By measuring the pulse width of the fuel injector, a technician can infer whether the MAF sensor is accurately reporting air flow—if there are anomalies in pulse width, it may indicate an issue with the MAF sensor.

In contrast, the functionality of the other sensors listed does not directly correlate with the injector pulse width. The Throttle Position sensor affects fuel mixture by controlling airflow but does not directly involve pulse width. The Vehicle Speed Sensor provides information about how fast the vehicle is moving,