Faulty humidity sensor reporting a high signal; Damaged, corroded or contaminated connector pins at the sensor; Signal wire shorted to the supply voltage or to another live circuit; Open circuit in the sensor ground wire, which can pull the signal high; Water, oil or dirt ingress in the sensor or airbox; Fault in the engine control unit or its sensor supply.

P00F5

Humidity Sensor Circuit High.

Generic
Powertrain
Generic code
Low severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
0: AreaFuel and air metering, auxiliary emission controls
F5: FaultThe specific fault in that area

What it means

P00F5 means the engine control unit has seen the signal from the humidity sensor sitting above its expected range for longer than the allowed time. The sensor is usually in the intake air path or fitted in the airbox, and may be combined with an air temperature sensor. The control unit uses the reading to refine fuelling, ignition and boost calculations, so it flags a circuit high fault when the voltage or frequency looks implausibly high.

Symptoms

Engine warning light on
Slightly rough running or hesitation under load in some cases
Marginally poorer fuel economy
Reduced performance if the control unit falls back to default values
Other related intake air or temperature codes stored alongside

Possible causes

Faulty humidity sensor reporting a high signallikely
Damaged, corroded or contaminated connector pins at the sensorlikely
Signal wire shorted to the supply voltage or to another live circuitpossible
Open circuit in the sensor ground wire, which can pull the signal highpossible
Water, oil or dirt ingress in the sensor or airboxpossible
Fault in the engine control unit or its sensor supplyrare

How to diagnose

Read the stored codes and freeze frame data, and note whether other intake air, temperature or sensor supply codes are present
Check for technical service bulletins or known issues for the specific model and engine
Visually inspect the sensor, its connector and the wiring for damage, corrosion, moisture or chafing
Look inside the airbox and intake pipe near the sensor for water, oil or debris
With the ignition on, view live humidity and intake temperature values and compare them with the ambient conditions
Check the sensor supply voltage and ground at the connector against the model's wiring diagram
Test the signal wire for a short to voltage or an open circuit, and wiggle the harness while watching live data
If the wiring is sound, swap or test with a known good sensor, following the manufacturer's procedure

How to fix

Replace the humidity sensor if it is confirmed faulty
Clean, repair or replace corroded or damaged connector terminals
Repair or replace any shorted, chafed or open wiring
Restore a good ground connection if it is faulty
Dry out and clear any water or contamination from the airbox, and fix the source of the ingress
Repair or replace the control unit only after the wiring and sensor have been fully ruled out

Can I keep driving?

Low severity

The car can normally be driven, as the control unit usually substitutes a default value. Book it in soon, especially if it runs roughly or loses power.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.