Samsung Air Conditioner E5 Error — Fix

What Does This Error Mean?

Samsung AC E5 error means the indoor and outdoor units have lost communication. Power off the unit at the breaker for 5 minutes, then restore power — this clears the majority of E5 errors caused by transient voltage issues.

Affected Models

Samsung Wind-Free AC
Samsung Split System AC
Samsung Inverter AC
Samsung Multi-Split AC

Common Causes

Transient voltage drop or power surge interrupting the communication signal
Loose or damaged communication wire between the indoor and outdoor units
Faulty PCB (control board) in the indoor or outdoor unit
Incorrect installation — reversed communication wire polarity
Refrigerant overcharge causing signal interference

How to Fix It

Power cycle the unit at the breaker.

Locate the circuit breaker for the air conditioner and switch it off. Wait 5 full minutes for the capacitors to discharge. Restore power and switch the AC back on. E5 caused by a transient power issue usually clears with a full power cycle.
Check the outdoor unit power supply.

Confirm the outdoor unit is receiving power — its status light or display should illuminate when power is on. If the outdoor unit shows no signs of power while the indoor unit is on, the communication between them has been cut.
Inspect the communication cable (qualified technician or experienced installer).

The communication wire runs between the indoor and outdoor units inside the refrigerant line set cover. Check for visible damage, pinching, or disconnected terminals at both ends. The wire must be connected in the correct polarity.

When to Call a Professional

If E5 persists after a power cycle and the communication wiring is intact, the PCB in either unit has failed. This requires a qualified HVAC technician to diagnose and replace the faulty board.