Code
P00F3
Generic
P — Powertrain
Humidity Sensor Circuit Range/Performance
Views:
UK: 25
EN: 41
RU: 34
AI status
Completed
Completed
100%
Causes
- Faulty humidity sensor (internal failure or contamination)
- Open or short in sensor signal wire
- Short to battery voltage or short to ground on the sensor circuit
- Poor or missing sensor ground or reference supply (typically 5 V)
- Corroded or loose connector or pin(s) at sensor or control module
- Water intrusion or physical damage to sensor
Symptoms
- Stored P00F3 DTC (may or may not illuminate MIL depending on manufacturer)
- Incorrect or implausible humidity reading in live data (e.g., stuck high/low or erratic)
- HVAC automatic mode behaves incorrectly (poor dehumidification, cycling, fogging)
- Reduced performance of climate-related features or sensor-dependent controls
- Intermittent faults or codes that appear after exposure to moisture
What to check
- Read and record freeze frame and live data with a scan tool (monitor humidity sensor value, reference voltage, and sensor status)
- Perform a visual inspection of sensor location, wiring, and connectors for damage, corrosion, or water
- Wiggle test wiring and connectors while monitoring live data for intermittent changes
- Check service information for sensor location and pinout before probing
- Verify connector pins are clean, straight and fully seated
Signal parameters
- Typical reference supply: 5.0 V (verify exact spec for vehicle)
- Typical signal output: ~0.5–4.5 V mapping roughly to 0–100% relative humidity (manufacturer-specific)
- Sensor impedance varies by design (often kΩ range); output should change smoothly with humidity
- Expected behavior: signal voltage should increase or decrease consistently when humidity changes (e.g., breathing on sensor or applying a damp cloth)
Diagnostic algorithm
- Connect a scan tool and note freeze frame data and when the code set
- Visually inspect sensor, harness and connector for corrosion, damage, or moisture; repair as needed
- Backprobe sensor connector: verify reference voltage (usually 5 V) with ignition ON; verify good ground
- With backprobe connected monitor signal voltage on live data; compare to expected range and look for erratic behavior
- Unplug sensor and check for short to ground or battery on the signal wire with a multimeter (infinite/low resistance as appropriate)
- Simulate humidity change (breath or damp cloth) while watching live data to confirm sensor responsiveness
- If wiring and connector check OK, replace humidity sensor with known-good part and retest
- If new sensor still faults, perform continuity tests between sensor connector and ECM connector/pins to rule out harness faults; repair any breaks or shorts
- Check for updated PCM/ECU software or TSBs if wiring and sensor test OK
- Clear codes and perform a test drive/soak test to confirm repair; if intermittent, monitor for recurrence
Likely causes
- Sensor internal failure or contamination (most common)
- Open/short in sensor signal or reference wiring
- Poor ground or 5 V reference supply
- Connector corrosion or water ingress
Fault status
Status
Humidity sensor circuit output is outside expected range or not performing; check sensor, wiring, and reference/ground.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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