E121, E122, E123 - Indoor temperature sensor error (Room, EVA IN, EVA OUT)

What does E121, E122, E123 mean?

The indoor unit's room temperature sensor (E121), evaporator inlet sensor (E122), or evaporator outlet sensor (E123) is reporting a short circuit or an open circuit. This means the sensor is not functioning correctly.

• Loose sensor connector
• Faulty temperature sensor
• Damaged wiring to the sensor

Click steps to track your progress.

1. 1

   Turn off the air conditioner's power at the circuit breaker.

2. 2

   Locate the specific temperature sensor (room, EVA IN, or EVA OUT) for the indoor unit.

3. 3

   Carefully check the sensor's connector to ensure it is securely plugged in.

4. 4

   Visually inspect the sensor wire for any damage or breaks.

5. 5

   If the issue persists, a technician may need to check the sensor's resistance value or replace the sensor.