Possible Causes

1. Incorrect insertion position of the ambient temperature sensor.

2. The ambient temperature sensor is not properly inserted into the main control board.

3. Damage to the ambient temperature sensor.

4. Damage to the sampling circuit of the main control board.

Solutions

1. Check the correctness of the sensor socket position.

2. Re-plug the ambient temperature sensor.

3. Verify if the sensor resistance matches the actual ambient temperature.

4. Replace the main control board.