Powertrain, generic · Fuel and air metering, auxiliary emission controls

P00F3 Humidity Sensor Circuit Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

The humidity sensor measures the relative humidity of the intake air; on documented vehicles it is built into the mass air flow sensor or a combined sensor. The engine control module uses the value, for example, to correct torque and in emission models. One documented design is capacitive and reports humidity as a pulsed signal with a duty cycle that the control module converts back. P00F3 is a plausibility fault: the reading is electrically valid but implausible. One manufacturer documents it being set shortly after starting in heat and extremely dry air; if the live value shows an implausibly low humidity, the air flow sensor with the integrated humidity sensor should be replaced, otherwise the fault is treated as intermittent.

Likely causes

Humidity sensor or combined air flow sensor faulty
Extremely dry and hot air making the test borderline
Contamination or oil mist on the sensing element

Symptoms

  • Check engine light on
  • Usually no noticeable symptoms
  • Slightly uneven torque or higher consumption possible

Repair estimate

DifficultyEasyDIY possible
Parts and labour€80–450
Time0.3–1 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

humidity sensormass air flow sensorhumidity sensor wiring

Related codes

P00F2P00F4P00F5P00F6

References: law.cornell.edu, static.nhtsa.gov, patents.google.com.