Unit shows E6, may not respond correctly to mode changes, sometimes associated with indoor–outdoor communication on split systems.

Safety first: Turn off the circuit breaker to the Sencor split air conditioner before touching any wiring.

• Step 1 – Verify wiring diagram: Open the indoor and outdoor unit terminal covers and compare the wiring to the Sencor installation diagram (usually labeled 1-2-3 and ground). Ensure the same numbers are connected between units.
• Step 2 – Tighten terminals: Check that all terminal screws are tight and that no copper wire is exposed or touching adjacent terminals.
• Step 3 – Inspect cable: Follow the communication cable along its route. Look for cuts, crushed sections, or water ingress at junction boxes.
• Step 4 – Power reset: Turn the breaker off for 10 minutes, then back on to reset both indoor and outdoor PCBs.
• Step 5 – Swap cable (if possible): Temporarily run a known-good cable between indoor and outdoor units to rule out cable damage.
• Step 6 – PCB diagnosis: If wiring is correct and E6 persists, either the indoor or outdoor PCB communication circuit is faulty. A technician should determine which board to replace.