SiBE07-618_DService Diagnosis 53Part 6Service Diagnosis1. Caution for Diagnosis............................................................................541.1 Troubleshooting with LED ......................................................................542. Problem Symptoms and Measures .......................................................553. Service Check Function ........................................................................564. Troubleshooting ....................................................................................594.1 Error Codes and Description ..................................................................594.2 Indoor Unit PCB Abnormality .................................................................604.3 Freeze-up Protection Control or Heating Peak-cut Control....................614.4 Fan Motor (AC motor) or Related Abnormality.......................................634.5 Thermistor or Related Abnormality (Indoor Unit)....................................644.6 Signal Transmission Error (between Indoor Unit and Outdoor Unit) ......654.7 Unspecified Voltage (between Indoor Unit and Outdoor Unit) ...............664.8 Outdoor Unit PCB Abnormality...............................................................674.9 OL Activation (Compressor Overload) ...................................................684.10 Compressor Lock ...................................................................................694.11 DC Fan Lock ..........................................................................................704.12 Input Overcurrent Detection ...................................................................714.13 Four Way Valve Abnormality..................................................................724.14 Discharge Pipe Temperature Control.....................................................744.15 High Pressure Control in Cooling ...........................................................754.16 Compressor System Sensor Abnormality ..............................................764.17 Position Sensor Abnormality ..................................................................774.18 CT or Related Abnormality .....................................................................794.19 Thermistor or Related Abnormality (Outdoor Unit).................................814.20 Electrical Box Temperature Rise............................................................834.21 Radiation Fin Temperature Rise ............................................................854.22 Output Overcurrent Detection ................................................................874.23 Refrigerant Shortage ..............................................................................894.24 Low-voltage Detection or Over-voltage Detection..................................914.25 Signal Transmission Error (on Outdoor Unit PCB).................................925. Check ....................................................................................................935.1 How to Check .........................................................................................93