When testing two types of MAP sensors, what voltage reading indicates that a sensor is most likely the frequency type?

When testing two types of MAP (Manifold Absolute Pressure) sensors, a constant voltage reading typically indicates that the sensor is a potentiometric type, not a frequency type. Frequency-type MAP sensors generate a voltage that fluctuates in relation to the changes in manifold pressure.

The correct choice reflects that a fluctuating voltage reading is characteristic of a frequency-type MAP sensor. Such sensors produce a varying voltage signal that corresponds to the changes in pressure, which can be observed as fluctuations on a voltmeter or oscilloscope. This behavior is due to the sensor converting changes in pressure into a signal with varying frequency, thereby resulting in fluctuating voltage outputs.

The option indicating a constant 2.5 volts would suggest that the sensor is measuring at a steady state, which does not align with the operation of a frequency-type MAP sensor. Frequency-type sensors are designed to signal changes actively by modifying their output voltage as pressure changes, leading to a reading that varies rather than remains constant.

In summary, a fluctuating voltage reading indicates the operation of a frequency-type MAP sensor, as it reflects real-time adjustments to pressure changes in the manifold.