Panasonic CS-E18QB4RW Service Manual page 83

15.4.24 F99 (DC Peak Detection)
Malfunction Decision Conditions
During startup and operation of cooling and heating, when inverter DC peak data is received by the outdoor internal
DC Peak sensing circuitry.
Malfunction Caused

DC current peak due to compressor failure.

DC current peak due to defective power transistor(s).

DC current peak due to defective outdoor unit PCB.

DC current peak due to short circuit.
Troubleshooting
83