Indoor unit displays E0 and will not respond to remote commands or only runs in a default mode.

Safety first: Turn off the breaker to the indoor unit and verify power is off before removing any covers.

Steps to try:

• Power reset: Turn the indoor unit OFF, switch the dedicated breaker OFF for 5–10 minutes, then turn it back ON. Try operating with the remote again.
• Check power quality: Confirm the indoor unit is on a stable, correctly sized circuit. Look for signs of recent surges (tripped breakers, other electronics failing).
• Inspect control board: Remove the front panel and access the indoor control box. Look for burnt components, bulged capacitors, or scorch marks on the indoor main PCB.
• Check wiring harnesses: Ensure all connectors to the indoor PCB are fully seated and not corroded or damaged.

When to stop: If E0 returns after a power reset and visual inspection, the EEPROM data on the board is likely corrupted. Replacement of the indoor main control board is typically required and should be done by a qualified HVAC technician to avoid damage to the new board.