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.
Medium severity. Can I keep driving?If the car is running normally, drive in moderation to a repair shop. If it loses power or another warning appears, do not continue.
Symptoms
- Check engine light on
- Usually no noticeable symptoms
- Slightly uneven torque or higher consumption possible
Most 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
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: easy
- It affects emissions.
What each character of P00F3 means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- 0: Subsystem depends on the code range
- F3: Specific fault in that system
Frequently asked questions
Can I keep driving with code P00F3?
If the car is running normally, drive in moderation to a repair shop. If it loses power or another warning appears, do not continue.
What causes code P00F3?
The most common causes are: 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.
Related codes
- P00F2Humidity Sensor Circuit/Open
- P00F4Humidity Sensor Circuit Low
- P00F5Humidity Sensor Circuit High
- P00F6Humidity Sensor Circuit Intermittent/Erratic
Sources
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.