Relative Humidity (RHS) Sensor
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The relative humidity sensor measures the humidity of the intake air by using a membrane allowing air to enter the cell while protecting it from liquid contaminants and dust. Relative humidity is the ratio of water vapor present in the air compared to the maximum amount the air can hold at that temperature and pressure.
The intake air humidity measurement is a key parameter for engine management. The PCM uses the input from the relative humidity sensor to adjust EGR flow rates in high humidity environments.