What it means
The control module monitors the humidity sensor signal. It sets this code when the signal rises above the expected range.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The cabin humidity sensor reports moisture levels to the control module, which uses the signal to help manage automatic climate control and reduce window fogging. This code is set when the humidity signal is higher than the module expects, which can happen if the signal is pulled toward battery voltage or the connector has excessive resistance.
Common causes
Most likely first.
- Signal wire shorted to battery
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
Symptoms
- Check-engine light on
- Automatic climate control may work less accurately
- Windshield may fog more easily
How to diagnose it
- Use a scan tool to record freeze-frame data and compare the humidity reading with cabin conditions to see whether it is implausibly high.
- Inspect the humidity sensor connector for corrosion, moisture, bent pins, or a poor fit that could add contact resistance.
- Trace the sensor signal and supply wires for pinching, damaged insulation, or contact with a battery-positive source.
- With the wiring diagram, check the sensor supply, ground, and signal circuit against the manufacturer's specification.
- If the wiring and connections are sound, test the humidity sensor output and replace it only if it remains out of specification.
Common fixes
- Clean and secure a corroded or loose humidity sensor connector.
- Repair a pinched supply wire or signal wire shorted to battery positive.
- Repair damaged wiring and restore proper routing away from battery-positive sources.
- Replace the humidity sensor if its output remains too high with sound wiring.
Can I keep driving?
This fault usually does not affect basic engine operation, but automatic climate control may respond poorly and the windshield may fog more readily. Keep the glass clear and avoid driving if fogging blocks your view.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.