Indoor unit displays E0 and the air conditioner will not start or respond to remote commands.

Safety first: Turn off the AC using the breaker and unplug the indoor unit (if plug-in type). Wait at least 5 minutes before touching any wiring.

• Step 1 – Power reset: Switch off the circuit breaker for 5–10 minutes to fully discharge the control board, then restore power and check if E0 clears.
• Step 2 – Check display-to-main board connections: Remove the front cover of the indoor unit, carefully remove the display panel, and inspect the ribbon cable and connectors going to the indoor main PCB. Reseat all connectors firmly.
• Step 3 – Inspect for board damage: Look for burn marks, swollen capacitors, or corrosion on the indoor PCB. If any are present, the board likely needs replacement.
• Step 4 – Replace indoor PCB if needed: Order a compatible Chigo indoor main PCB using the model number from the rating label. Disconnect power, label and remove all connectors from the old board, swap in the new board, and reconnect exactly as before.
• When to call a technician: If E0 persists after a power reset and connector check, or if you are not comfortable working around electronics, contact an HVAC technician to test and replace the PCB.