Daikin Aurora Series Service Manual page 270

Troubleshooting by Error Code
257
A
The insulation
resistance of the fan
motor is not more than
1 MΩ.
NO
CHECK 4
Is the power
transistor normal?
YES
Connect and disconnect the
following connectors:
(1) X6A (Inverter PCB)↔X28A (A1P)
(2) X63A (Inverter PCB)↔X40A (A1P)
The
inverter PCB has
damage.
NO
Turn ON the power supply,
and then press the ON button.
The
system enters
standby mode before the
outdoor fan starts
rotating.
NO
The
system enters
standby mode before
completing the startup
operation of the
compressor.
NO
The error U2 recurs.
NO
CHECK 4 Refer to page 286.
YES
NO
YES
YES
YES
YES
SiUS341802E
Replace the fan motor.
If the motor gets severely
damaged, the inverter
PCB should also be
replaced.
Replace the inverter PCB.
RXLQ-TATJU,
RXLQ-TAYDU: A3P
RXLQ-TAYCU,
RXYQ-TAYCU: A4P
Replace the inverter PCB.
If the inverter PCB gets
severely damaged, the
compressor and the fan
motor may have been
damaged.
Replace the inverter PCB.
Replace the inverter PCB.
If the inverter PCB gets
severely damaged, check
for the compressor.
Check for wirings.
Continue operation.
The error could have
resulted from causes such
as instantaneous power
failure.
Service Diagnosis