Thermostat displays E2 and temperature reading is inaccurate or blank

Safety: Turn off power to the furnace/air handler at the breaker before handling the thermostat or wiring.

• Inspect thermostat front and vents: Remove the thermostat from the wall plate. Check for condensation, insect debris, or metallic dust around the vent slots and sensor area. Clean gently with a soft brush and compressed air.
• Check for moisture: If the thermostat is installed near a bathroom or kitchen, humidity may have caused a short. Allow the thermostat to dry in a warm, dry location for 24 hours, then reinstall.
• Verify wiring is not touching sensor area: Ensure low‑voltage wires are seated in the wall plate terminals and not bent up into the thermostat body where they could short the sensor.
• Reset thermostat: Perform a factory reset from the settings menu. Reconfigure system type and Wi‑Fi. Monitor if E2 returns.
• Replace thermostat if E2 persists: A persistent E2 indicates a failed internal sensor or PCB. Replace the Honeywell Home smart thermostat with a compatible model.