Thermostat displays E1 and will not detect indoor temperature correctly

Safety first: Turn off power to the thermostat at the HVAC breaker or by removing it from the sub-base if it is powered only by low voltage.

Steps to address E1 sensor fault:

• 1. Inspect thermostat location: Ensure the thermostat is not exposed to direct sunlight, drafts from supply vents, or heat sources that could cause extreme readings. While this won't usually trigger E1, it can contribute to sensor stress.
• 2. Remove thermostat from wall: Gently pull the thermostat off its sub-base. Check for signs of condensation, water damage, or corrosion on the back of the unit and around the sensor opening.
• 3. Dry and clean: If moisture is present, allow the thermostat to dry completely for several hours in a dry indoor area. Do not use heat guns or hair dryers. Lightly dust the sensor area with compressed air.
• 4. Power cycle: Reinstall the thermostat on the sub-base and restore power. Perform a factory reset from the settings menu if available, then reconfigure basic settings.
• 5. Compare readings: Use a reliable room thermometer placed next to the thermostat. If the thermostat reading is wildly inaccurate or E1 returns, the internal sensor is likely failed.
• 6. Replace thermostat: The internal sensor is not field-repairable on most Goodman smart thermostats. Replace the thermostat with a compatible Goodman smart model and reconfigure system type and staging.