LG Therma V fault CH03

What it means

No communication between Main PCB (Indoor) and wired remote controller.

Likely causes

1. Incorrect cable connection and burnout
2. Noise interference
3. Wired remote controller burnout
4. Main PCB burnout
5. Remote control terminal block not properly connected
6. Intermediate connection formed by twisting inner wire strands without soldering
7. Communication line shorted or disconnected
8. Main PCB(Indoor) CN-REMO voltage not present (fault on Main PCB)
9. Noise near wired remote control or communication line

Where to start

1. Check if wired remote control connector and terminal block are properly connected; if not, reconnect to CN-REMO for wired remote controller (connector, terminal terminal)
2. Check if the specifications of the wired remote controller cable are recommended; if not, replace cable (use AWG 24, 3 or higher)
3. Check if the communication line is normal without short circuit or disconnection; if not, replace cable