Indoor Room Temperature Sensor Open or Short Circuit

What it means

This code appears on Gree split air conditioners when the control board reads an impossible value from the indoor room temperature sensor, meaning the sensor or its circuit is open or shorted. This sensor measures the air entering the indoor unit; without it the unit cannot tell when the room has reached the set temperature, so it stops cooling or runs erratically depending on the model. The same code can mean something else on other brands.

Models covered: Gree split (wall-mounted) air conditioners, mainly inverter models; the code shows on the indoor unit display. Older non-inverter models may show fewer codes.

Related codes: F2F3F4F5C5

Symptoms3

• The code appears at start-up or after a few minutes.
• The unit does not cool, or cools without cycling off at the set temperature.
• The room ends up colder or warmer than the setting.

Possible causes5

• Loose or corroded sensor connector on the indoor control board, which is the most common cause.
• Failed sensor (thermistor) from moisture or age.
• Broken or chafed sensor wire from rubbing, rodents or heat.
• Water leaking inside the indoor unit onto the sensor or connector.
• Faulty sensor input circuit on the indoor control board, which is less common.

How to diagnose5

1. Switch off at the breaker for a few minutes and restart to see if the code is permanent.
2. The technician checks the sensor connector on the indoor control board and reseats it firmly.
3. The technician removes the sensor, measures its resistance and compares it with the Gree resistance table at a known temperature.
4. The technician inspects the wire along its length for breaks or chafing.
5. If the sensor and wire are fine, the technician tests the board with a known-good sensor.

How to fix5

1. Clean and firmly reseat the connector.
2. Repair and insulate the damaged wire.
3. Replace the sensor with the correct part for the model and fit it in its original position.
4. Replace the indoor control board only if its input circuit is proven faulty.
5. Run the unit and confirm the code is gone and cooling is normal.

A connector clean or a new sensor is usually enough and cheap; the cost only rises if the control board has to be replaced.

Prices are rough estimates including the part and the technician’s fee, and vary with brand, model and part source.
Prices last updated: September 2026

Frequently asked questions