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Fronius International GmbH inverter error codes

Fronius International GmbH · An established brand in the UK. 64 codes across 2 product families, each taken from the manufacturer’s manuals. Fronius International GmbH technical support ↗

Find a Fronius International GmbH engineer →64 codes · reviewed 24 September 2026

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Type the code on your display or a word from its meaning. Each code opens its own page with what it means, whether it is safe and what you can check.

64 codes

CodeMeaningStops?Homeowner check?
102
AC voltage too high
YesYes
103
AC voltage too low
YesYes
105
AC frequency too high
YesYes
106
AC frequency too low
YesYes
107
No AC grid
YesYes
108
Stand-alone operation detected
YesYes
112
RCMU error
YesYes
240-243
Arc detection
YesYes
301
Overcurrent (AC)
PartlyYes
302
Overcurrent (DC)
PartlyYes
303
Power stage set overtemperature
PartlyYes
304
Internal temperature too high
PartlyYes
306
LOW PV OUTPUT - intermediate circuit voltage too low for feeding energy into the grid
PartlyYes
307
LOW PV VOLTAGE - DC input voltage too low for feeding energy into the grid
PartlyYes
308
Intermediate circuit overvoltage
PartlyYes
309
DC input voltage MPPT 1 too high
PartlyYes
313
DC input voltage MPPT2 too high
PartlyYes
401
Unable to communicate with the power stage set
YesYes
406
Power stage set temperature sensor faulty
YesYes
407
Internal temperature sensor faulty
YesYes
408
Direct current feeding in detected
YesYes
415
Safety cut-out via option card or RECERBO has triggered
YesYes
416
No communication possible between power stage set and control system
YesYes
417
Hardware ID problem
YesYes
425
Unable to communicate with the power stage set
YesYes
431
Software problem
YesYes
436
Functional incompatibility (PC boards not compatible, e.g. after board replacement)
YesYes
438
Functional incompatibility (PC boards not compatible)
YesYes
443
Intermediate circuit voltage too low or asymmetric
YesYes
445
Impermissible limit value settings
YesYes
447
Insulation fault
YesYes
448
Neutral conductor not connected
YesYes
451
Memory error detected
YesYes
452
Communication error between the processors
YesYes
453
Short-term grid voltage error
YesYes
454
Short-term grid frequency error
YesYes
456
Anti-islanding function is no longer being implemented correctly
YesYes
457
Grid relay sticking
YesYes
463
Reversed AC polarity, AC connector inserted incorrectly
YesYes
474
RCMU sensor faulty
YesYes
475
Solar module ground, insulation fault (connection between solar module and earth)
YesYes
479
Intermediate circuit voltage relay is switched off
YesYes
482
Start-up incomplete
YesYes
485
CAN transmit buffer is full
YesYes
489
Permanent overvoltage on intermediate circuit capacitor (five 479 status codes in a row)
YesYes
502
Insulation error on the solar modules
NoYes
509
No energy fed into the grid in the past 24 hours
NoYes
515
Unable to communicate with filter
NoYes
517
Power derating caused by too high a temperature
PartlyYes
522
DC low String 1
NoYes
523
DC low String 2
NoYes
560
Power derating caused by overfrequency
PartlyYes
566
Arc detector switched off (e.g. during external arc monitoring)
NoYes
710
Solar Net - Keep alive signal missing
NoYes
751
Time lost
NoYes
757
Hardware error in the Real Time Clock module
YesYes
766
Emergency power limitation has been activated (max. 750 W)
PartlyYes
1001
After 24 hours of continuous feed-in an insulation measurement must be carried out.
PartlyYes
1024
A configuration change requires a restart.
PartlyYes
1030
A device in the WSD (wired shutdown) chain has interrupted the signal line (e.g. surge protection device tripped) or the factory bypass was removed without a trigger device; operating LED flashes red.
YesYes
1036
When connecting to the public grid the grid frequency was exceeded.
YesYes
1112
Grid voltage exceeds the stored limit value so the inverter reduces power.
PartlyYes
1175
Insufficient sunlight / poor weather.
PartlyYes
1196
Only appears when starting for the first time.
NoYes