Fronius Symo Fault Codes

Fronius Symo Fault Codes

The Fronius Symo is a popular choice among Australian homeowners and businesses for its reliability and efficiency. However, there might be times when your inverter communicates a hiccup via a fault code. These codes can be found on the inverter’s display or its online interface. They serve as a guidepost, helping you identify and resolve issues.

This article dives deep into the fault codes for the Fronius Symo, offering a clear understanding by listing the code number, explaining what it indicates, detailing the behaviour associated with the fault, and suggesting remedies.

Fronius Symo fault codes beginning with 1xx

Code	Description	Behaviour	Remedy
STATE 102	AC voltage too high	Following careful testing and when the grid conditions are within the permissible range again, the inverter will resume feeding energy into the grid.	Check grid connections: If this STATE code keeps recurring contact your solar power system installer.
STATE 103	AC voltage too low
STATE 105	AC frequency too high
STATE 106	AC frequency too low
STATE 107	AC grid outside the permissible limits
STATE 108	Stand alone operation detected
STATE 112	RCMU error

Fronius Symo fault codes beginning with 3xx

Code	Description	Behaviour	Remedy
STATE 301	Overcurrent (AC)	Short-term interruption while feeding energy into the grid due to over current in the inverter. The inverter resumes with its startup routine.	Fault is rectified automatically; if this STATE code is displayed all the time: notify your local Fronius service partner.
STATE 302	Overcurrent (DC)
STATE 303	DC module over temperature	Short term interruption while feeding energy into the grid due to over temperature. The inverter resumes with its startup routine.	Purge openings for cooling air and heat sink if necessary; fault is rectified automatically; if this STATE code keeps recurring contact your solar power system installer.
STATE 304	AC module over temperature
STATE 305	No power being fed in, despite closed relay	Short term interruption while feeding energy into the grid due to over temperature. The inverter resumes with its startup routine.	fault is rectified automatically; if this STATE code keeps recurring contact your solar power system installer.
STATE 306	PV output too low for feeding energy into the grid	Short term interruption while feeding energy into the grid. The inverter resumes with its startup routine.	Fault is rectified automatically; if this STATE code occurs when there is sufficient insolation (sunlight) contact your solar power system installer. IMPORTANT! Due to the low level of insolation (sunlight) early in the morning and in the evening, the STATE codes 306 (LOW PV OUTPUT) and 307 LOW PV VOLTAGE) are displayed routinely at these times of day. These STATE codes do notindicate any kind of fault.
STATE 307	LOW PV VOLTAGE DC input voltage too low for feeding energy into the grid
STATE 308	Intermediate circuit voltage too high	Short term interruption while feeding energy into the grid. The inverter resumes with its startup routine.	Fault is rectified automatically; if this STATE code is displayed all the time: notify your local Fronius service partner.
STATE 309	DC input voltage MPPT 1 too high
STATE 311	Polarity of DC strings reversed
STATE 313	DC input voltage MPPT 2 too high
STATE 314	Current sensor calibration timeout	Short term interruption while feeding energy into the grid. The inverter resumes with its startup routine.	Fault is rectified automatically; if this STATE code is displayed all the time: notify your local Fronius service partner.
STATE 315	AC current sensor erro
STATE 316	Interrupt Check fail
STATE 325	Overtemperature in the connection area
STATE 326	Fan 1 error
STATE 327	Fan 2 error

Fronius Symo fault codes beginning with 4xx

Code	Description	Behaviour	Remedy
STATE 401	No communication possible with the power stage set	The inverter will automatically attempt to connect again and, if possible, will resume feeding energy into the grid.	If the STATE code is displayed all the time contact your local Fronius Service Partner
STATE 406	AC module temperature sensor faulty (L1)
STATE 407	AC module temperature sensor faulty (L2)
STATE 408	DC component measured in the grid too high
STATE 412	Fixed voltage mode has been selected instead of MPP voltage mode and the fixed voltage has been set to too low or too high a value	–	If this STATE code persists contact your solar power system installer
STATE 415	Safety cut out via option card or RECERBO has triggered	The inverter is not feeding any energy into the grid.	If the STATE code is displayed all the time contact your local Fronius Service Partner
STATE 416	No communication possible between power stage set and control system	The inverter will automatically attempt to reconnect again and, if possible, will resume feeding energy into the grid.
STATE 417	Hardware ID problem		Update the inverter firmwarewith the latest firmware here; if the STATE code is displayed all the time after the firmware update contact your local Fronius Service Partner.
STATE 419	Unique ID conflict
STATE 420	No communication possible with the Hybrid manager
STATE 421	HID range error
STATE 425	No communication with the power stage set possible
STATE 426-428	Possible hardware fault
STATE 431	Software problem	The inverter is not feeding any energy into the grid.	Carry out an AC reset (switch the AC circuit breaker off and on); update inverter firmware; if this status code is displayed all the time please contact your local Fronius Service Partner.
STATE 436	Functional incompatibility (one or more PC boards in the inverter are not compatible with each other, e.g. after a PC board has been replaced.	The inverter will automatically attempt to connect again and, if possible, will resume feeding energy into the grid.	Update the inverter firmwarewith the latest firmware here; if the STATE code is displayed all the time after the firmware update contact your local Fronius Service Partner.
STATE 437	Power stage set problem
STATE 438	Functional incompatibility (one or more PC boards in the inverter in the inverter are not compatible with each other, e.g. after a PC board has been replaced)
STATE 443	Intermediate circuit voltage too low or asymmetric	The inverter is not feeding any energy into the grid.	If the status code is displayed all the time contact your local Fronius Service Partners.
STATE 445	– Compatability error (e.g. due to replacement of a PC board) – invalid power stage set configuration	The inverter is not feeding any energy into the grid for safety reasons.	Update the inverter firmwarewith the latest firmware here; if the STATE code is displayed all the time after the firmware update contact your local Fronius Service Partner.
STATE 447	Insulation fault		If this status code is displayed all the time: notify a local Fronius Service Partner
STATE 448	Neutral conductor not connected
STATE 450	Guard cannot be found
STATE 451	Memory error detected	The inverter will automatically attempt to connect again, and if possible, will resume feeding energy into the grid.	If the STATE code is displayed all the time: notify your local Fronius Service Partner.
STATE 452	Communication error between the processors
STATE 453	Grid voltage and power stage set are incompatible
STATE 454	Grid frequency and power stage set are incompatible
STATE 456	Anti-islanding function is no longer implemented correctly
STATE 457	Grid relay sticking or the neutral conductor ground voltage is too high	The inverter is not feeding any energy into the grid.	Check the grounding (the neutral conductor ground voltage must be less than 30V. If problem persists contact your local Fronius Service Partner.
STATE 458	Error when recording the measuring signal		Contact your local Fronius Service Partner.
STATE 459	Error when recording the measuring signal for the insulation test
STATE 460	Reference voltage source for the digital signal processor (DSP) is working out of tolerance
STATE 461	Fault in the DSP data memory
STATE 462	Error with DC feed monitoring routine
STATE 463	Reversed AC polarity, AC connector inserted incorrectly
STATE 474	RCMU sensor faulty
STATE 475	Solar panel ground fault, insulation fault (connection between solar panel and ground)
STATE 476	Driver supply voltage too low
STATE 480, 481	Functional incompatibility (one or more PC boards in the inverter are not compatible with each other, e.g. after a PC board has been replaced)		Update the inverter firmwarewith the latest firmware here; if the STATE code is displayed all the time after the firmware update contact your local Fronius Service Partner.
STATE 482	Setup after the initial start-up was interrupted		Perform AC reset (turn AC circuit breaker off and on), complete startup.
STATE 483	Voltage UDC fixed on MPP2 string out of limits		Check the MPP settings; if the status code is displayed all the time contact your local Fronius Service Partner
STATE 485	CAN transmit buffer is full		Carry out an AC reset (turn AC circuit breaker off and on), if the STATE code continues to be displayed notify your local Fronius Service Partner.

Fronius Symo fault codes beginning with 5xx

Code	Description	Behaviour	Remedy
STATE 502	Insulation error on the solar panels	Warning message is shown on the display	If this STATE code keeps recurring, contact your solar power system installer.
STATE 509	No energy fed into the grid in the past 24 hours		Acknowledge STATE code; check whether all the conditions for the problem free feeding of energy into the grid have been met. If the STATE code is displayed all the time: look out for further STATE codes.
STATE 515	No communication with filter possible		If the status code is displayed all the time notify your local Fronius Service Partner.
STATE 516	No communication possible with the storage unit	Storage unit warning message.
STATE 517	Power derating caused by too high a temperature	When power derating occurs, a warning message is shown on the display	Purge cooling air openings and heat sink if necessary; fault is rectified automatically; if this STATE code keeps recurring contact your solar power system installer.
STATE 518	Internal DSP malfunction	Warning message on the display	If this STATE code keeps recurring contact your solar power system installer.
STATE 519	No communication possible with the storage unit	Storage unit warning message
STATE 520	No energy fed into the grid by MPPT1 in the past 24 hours	Warning message is shown on the display	Acknowledge status code; check whether all the conditions for the problem free feeding of energy into the grid has been met. If this STATE code keeps recurring contact your solar power system installer.
STATE 522	DC low string 1		Warning message on the display
STATE 523	DC low string 2		Warning message on the display
STATE 558, 559	Functional incompatibility (one or more PC boards in the inverter are not compatible with each other, e.g. after a PC board has been replaced)		Update the inverter firmwarewith the latest firmware here; if the STATE code is displayed all the time after the firmware update contact your local Fronius Service Partner.
STATE 560	Derating caused by over-frequency	This STATE code is displayed when the grid frequency becomes excessively high. The inverter will then reduce its output. The status indicator will continue to be displayed until the inverter has returned to normal operation.	As soon as the grid frequency is back within the permissible range and the inverter has returned to normal operation, the fault is rectified automatically. If this STATE code keep recurring contact your solar power system installer.
STATE 564	Functional incompatibility (one or more PC boards in the inverter are not compatible with each other, e.g. after a PC board has been replaced)	Warning message on the display	Update the inverter firmwarewith the latest firmware here; if the STATE code is displayed all the time after the firmware update contact your local Fronius Service Partner.
STATE 566	Arc detector switched off (e.g. during external arc monitoring)	The STATE code is displayed every day until the arc detector is reactivated.	No error Confirm status code by pressing ‘Enter’.
STATE 567	Grid Voltage Dependent Power Reduction is active	This state code is a warning informing you that the Grid Voltage Dependent Power Reduction mode (GVDPR or Volt – Watt mode) has been activated and the inverter will continue to operate with reduced power output. This is because the grid voltage has exceeded 250Vac and the GVDPR has been enabled to try to reduce the voltage rise at the inverters terminals. This mode must be enabled by default in accordance with the latest Australian Standards.	Acknowledge status code; if this STATE 567 code keeps recurring contact your local solar power system installer. Find out more about the STATE 567 message here

Fronius Symo fault codes beginning with 6xx

Code	Description	Behaviour	Remedy
STATE 601	CAN bus is full	The inverter is not feeding any energy into the grid.	Update the inverter firmwarewith the latest firmware here; if the STATE code is displayed all the time after the firmware update contact your local Fronius Service Partner.
STATE 603	AC module temperature sensor faulty (L3)	The inverter will automatically attempt to connect again and, if possible, will resume feeding energy into the grid.	If this STATE code keeps recurring contact your solar power system installer.
STATE 604	DC module temperature sensor faulty
STATE 607	RCMU error	The inverter is not feeding any energy into the grid.	Reset status code by pressing ‘Enter’. The inverter resumes the feeding of energy into the grid; if the status code keeps appearing, check the complete solar system for damage.
STATE 608	Functional incompatibility (one or more PC boards in the inverter are not compatible with each other, e.g. after a PC board has been replaced)	The inverter is not feeding any energy into the grid.	Update the inverter firmwarewith the latest firmware here; if the STATE code is displayed all the time after the firmware update contact your local Fronius Service Partner.

Fronius Symo fault codes beginning with 7xx

Code	Description	Behaviour	Remedy
STATE 701-716	Provides information about the internal processor status	Warning message is shown on the display	If the STATE code is displayed all the time notify your local Fronius Service Partner.
STATE 721	EEPROM has been re-initialised		Acknowledge STATE code; If the STATE code is displayed all the time contact your local Fronius Service Partner
STATE 722-730	Provides information about the internal processor status		If the STATE code is displayed all the time contact your local Fronius Service Partner
STATE 731	Initialisation error – USB flash drive is not supported		Check or replace USB flash drive. Check the file system on the USB flash drive. If the STATE code is displayed all the time notify your local Fronius Service Partner.
STATE 732	Initialisation erro – Over current on USB stick
STATE 733	No USB flash drive connected		Connect or check the USB flash drive. If STATE code is displayed all the time contact your local Fronius Service Partner.
STATE 734	Update file not recognised or not present		Check update file (e.g. for correct file name). If STATE code is displayed all the time contact your local Fronius Service Partner.
STATE 735	Update file does not match the device, update file too old	Warning message appears on the display, update process is interrupted.	Check the update file with the latest firmware here; if the STATE code is displayed all the time after the firmware update contact your local Fronius Service Partner.
STATE 736	Write or read error occurred	Warning message is shown on the display	Check USB flash drive and the data contained on it or replace USB flash drive. Never unplug a USB flash drive if the ‘Data Transmission’ LED is still flashing or lit. If the STATE code is displayed all the time contact your local Fronius Service Partner.
STATE 737	File could not be opened		Remove and then reinsert USB flash drive; check or replace USB flash drive
STATE 738	Log file cannot be saved (e.g. USB flash drive is write protected or full)		Create storage space, remove write protection, check or replace USB stick if necessary. If STATE code is displayed all the time contact your local Fronius Service Partner.
STATE 740	Initialisation error-error in file system on USB flash drive		Check USB flash drive; reformat on PC for FAT12, FAT16 or FAT32.
STATE 741	Error during recording of logging data		Remove and then reinsert USB flash drive; check or replace USB flash drive
STATE 743	Error occurred during update process		Repeat the update process, check USB stick. If STATE code is displayed all the time contact your local Fronius Service Partner.
STATE 745	Update file corrupt	Warning message appears on the display, update process is interrupted.	Re-download update file. If STATE code is displayed all the time contact your local Fronius Service Partner.
STATE 746	Error occurred during update process		Wait for 2 minutes, then start the update again. If STATE code is displayed all the time contact your local Fronius Service Partner.
STATE 751	Time lost	Warning message is shown on the display	Reset the time and date on the inverter. Check update file (e.g. for correct file name). If STATE code is displayed all the time contact your local Fronius Service Partner.
STATE 752	Real Time Clock module communication error	Warning message is shown on the display
STATE 753	Internal error: Real Time Clock module is in emergency mode	Time may be inaccurate or lost (feeding energy into the grid normal)
STATE 754-755	Provides information about the processor status	Warning message on the display	If STATE code is displayed all the time contact your local Fronius Service Partner.
STATE 757	Hardware error in the Real Time Clock module	Error message is shown on the display; the inverter is not feeding any energy into the grid.
STATE 758	Internal error: Real Time Clock module is in emergency mode	Time may be inaccurate or lost (feeding energy into the grid normal).	Reset time and date on the inverter
STATE 760	Internal hardware error	Error message is shown on the display.	If STATE code is displayed all the time contact your local Fronius Service Partner.
STATE 761-765	Provides information about the internal processor status	Warning message is shown on the display.
STATE 766	Emergency power de-rating has been activated	Error message is shown on the display.
STATE 767	Provides information about the internal processor status	Warning message is shown on the display.
STATE 768	Different power limitation in the hardware modules
STATE 772	Storage unit not available
STATE 773	Software update group 0 (invalid country setup)
STATE 775	PMC power stage set not available	Warning message is shown on the display.	Press ‘Enter’ key to acknowledge error. If STATE code is displayed all the time contact your local Fronius Service Partner.
STATE 776	Invalid device type	Warning message is shown on the display.
STATE 781-794	Provides information about the internal processor status	Warning message is shown on the display.	If STATE code is displayed all the time contact your local Fronius Service Partner.