Panasonic CS-RE18QKE Service Manual page 79

15.5.28 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

Checking the power transistor.

Never touch any live parts for at least 10 minutes after turning off the circuit breaker.

If unavoidable necessary to touch a live part, make sure the power transistor's supply voltage is below 50V using
the tester.

For the UVW, make measurement at the Faston terminal on the board of the relay connector.
Tester's negative terminal
Tester's positive terminal
Normal resistance
Abnormal resistance
Power transistor (+)
UVW Power transistor (+)
UVW Power transistor (-)
Several kΩ to several MΩ
0 or ∞
79
UVW
UVW Power transistor (-)