C18
Bosch EasyControl Internal Humidity / Air Quality Sensor Fault

Bosch EasyControl shows error C18 and reports that the internal humidity or air quality sensor (if present) is malfunctioning.

Advertisements

Possible Causes

Sensor contamination by dust or moisture, Internal sensor electronics failure, Firmware misreading sensor data, Installation in high-humidity environment (e.g., bathroom)

How to Fix / Troubleshooting

Safety first: Do not open the EasyControl casing.

  • 1. Check location: Ensure the EasyControl is not installed in a bathroom, kitchen directly above a hob, or other high-humidity area. Relocate if necessary.
  • 2. Gentle cleaning: Remove the EasyControl from the wall plate (power off) and gently blow away dust from vents using dry compressed air. Do not use liquids.
  • 3. Firmware update: Update the EasyControl firmware via the app to ensure correct sensor handling.

Professional help: Persistent C18 indicates a failed internal sensor; the EasyControl unit may need replacement.

Advertisements

Repair Difficulty

Easy 2/5

Required Part

Bosch EasyControl internal humidity sensor
Check Price on Amazon

We may earn a commission from links on this page.

Advertisements