Fronius state codes are like your solar inverter’s way of communicating with you. Just as your car has a “check engine” light to alert you to potential issues, your Fronius inverter uses these codes to provide updates on the system’s performance. They appear on your inverter’s display and serve as helpful messages to guide you.
Why Are These Codes Important?
Fronius state codes give you insights into:
- Whether your solar system is running smoothly
- Minor issues that might resolve on their own
- Larger problems that require professional attention
Understanding these codes ensures your solar system remains efficient and functional, helping you address issues before they escalate.
Types of Codes You Might Encounter
| Error Code | Description | Solution |
|---|---|---|
| 102 | AC voltage too high | submit a maintenance service request |
| 103 | AC voltage too low | submit a maintenance service request |
| 105 | AC frequency too high | submit a maintenance service request |
| 106 | AC frequency too low | submit a maintenance service request |
| 107 | AC grid outside allowed limits | submit a maintenance service request |
| 108 | Independant operation detected | submit a maintenance service request |
| 112 | A resididual current monitoring unit (RCMU) error has occured | submit a maintenance service request |
| 141 | Grid frequency jump too high | submit a maintenance service request |
| 301 | Excess AC Current | These faults generally fix themselves within a few hours. If the fault persists restart the system. If the error is still occuring, submit a maintenance service request. |
| 302 | Excess DC Current | These faults generally fix themselves within a few hours. If the fault persists restart the system. If the error is still occuring, submit a maintenance service request. |
| 303 | DC module overheating | These faults generally fix themselves within a few hours. If the fault persists restart the system. If the error is still occuring, submit a maintenance service request. |
| 304 | AC module overheating | These faults generally fix themselves within a few hours. If the fault persists restart the system. If the error is still occuring, submit a maintenance service request. |
| 305 | Power is not being fed in, although relay is closed | These faults generally fix themselves within a few hours. If the fault persists restart the system. If the error is still occuring, submit a maintenance service request. |
| 306 | PV output is too low to feed | This fault will fix itself, if the fault keeps showing even when sufficient sunlight contact us. NOTE: These codes are shown at morning and night because of the low levels of sunlight at these times. |
| 307 | PV output is too low to feed | Shown morning and night because of the low levels of sunlight at these times. If persistant throughout day, submit a maintenance service request. |
| 308 | The intermediate circuit voltage is too high | These faults generally fix themselves within a few hours. If the fault persists restart the system. If the error is still occuring, submit a maintenance service request. |
| 309 | DC input voltage MPPT 1 is too high | These faults generally fix themselves within a few hours. If the fault persists restart the system. If the error is still occuring, submit a maintenance service request. |
| 311 | Polarity of the DC strings is reversed | These faults generally fix themselves within a few hours. If the fault persists restart the system. If the error is still occuring, submit a maintenance service request. |
| 313 | DC input voltage MPPT 2 is too high | These faults generally fix themselves within a few hours. If the fault persists restart the system. If the error is still occuring, submit a maintenance service request. |
| 314 | Current sensor calibration timeout | These faults generally fix themselves within a few hours. If the fault persists restart the system. If the error is still occuring, submit a maintenance service request. |
| 315 | AC current sensor error | submit a maintenance service request |
| 316 | Interrupt check fail | submit a maintenance service request |
| 317 | Unbalanced intermediate circuit voltage | submit a maintenance service request |
| 318 | DC back current detected | submit a maintenance service request |
| 325 | Connection area overheating | submit a maintenance service request |
| 326 | Error with fan 1 | submit a maintenance service request |
| 327 | Error with fan 2 | submit a maintenance service request |
| 401 | AC Voltage too high | submit a maintenance service request |
| 406-407 | Temperature sensor for AC module is faulty | submit a maintenance service request |
| 408 | DC component measures in the grid too high | submit a maintenance service request |
| 412 | Fixed voltage mode has selected instead of MPP voltage mode.Fixed voltage mode has been set at the wrong value. | Restart system. If code is ongoing submit a maintenance service request. |
| 415 | Safety cut out has triggered via option card or RECERBO | Restart system. If code is ongoing submit a maintenance service request. |
| 416 | Power stage set has no communication with control system | Restart system. If code is ongoing submit a maintenance service request. |
| 417-419 | Hardwire ID issue | Inverter firmware needs to be updated. This needs to be done with enough daylight for whole update or the inverter will need to be replaced with likely no warranty. Submit a maintenance service request. |
| 420 | Unable to communicate with Hybrid manager | Inverter firmware needs to be updated. This needs to be done with enough daylight for whole update or the inverter will need to be replaced with likely no warranty. Submit a maintenance service request. |
| 421 | HID range error | Inverter firmware needs to be updated. This needs to be done with enough daylight for whole update or the inverter will need to be replaced with likely no warranty. Submit a maintenance service request. |
| 425 | Unable to communicate with the power stage set | Inverter firmware needs to be updated. This needs to be done with enough daylight for whole update or the inverter will need to be replaced with likely no warranty. Submit a maintenance service request. |
| 426-428 | Hardwire fault | Inverter firmware needs to be updated. This needs to be done with enough daylight for whole update or the inverter will need to be replaced with likely no warranty. Submit a maintenance service request. |
| 431 | Software fault | Conducat an AC reset (Switch the AC circuit breaker off and on) ‘ then update the inverter firmware as above. If the fault code continues to appear submit a maintenance service request. |
| 436 | Functional incompatibility | Inverter firmware needs to be updated. This needs to be done with enough daylight for whole update or the inverter will need to be replaced with likely no warranty. |
| 437 | Power stage fault | Inverter firmware needs to be updated. This needs to be done with enough daylight for whole update or the inverter will need to be replaced with likely no warranty. |
| 438 | Functional incompatibility | Inverter firmware needs to be updated. This needs to be done with enough daylight for whole update or the inverter will need to be replaced with likely no warranty. |
| 443 | The intermediate circuit voltage is too low or asymmetric | Generally will correct itself within a few hours. If not, restart the system. |
| 445 | Compatibility fault. Invalid power stage set configuration. | As per code 436 |
| 447 | Insulation problem | Generally will correct itself within a few hours. If not, restart the system. If code stays on for a prolonged period submit a maintenance service request. |
| 448 | The neutral conducted ios not connected | Generally will correct itself within a few hours. If not, restart the system. If code stays on for a prolonged period submit a maintenance service request. |
| 450 | The guard can’t be found | Generally will correct itself within a few hours. If not, restart the system. If code stays on for a prolonged period submit a maintenance service request. |
| 451 | Memory fault detected | Generally will correct itself within a few hours. If not, restart the system. If code stays on for a prolonged period submit a maintenance service request. |
| 452 | Communication problem between processors | Installer to attend site and disconnect / reconnect terminals and tighten screws. |
| 453 | Power stage set and grid voltage not compatible. | Customer restart system, then monitor over a few days. If the system is continually showing the fault for approx 3 days request a maintenance service request. |
| 454 | Power stage set and grid frequency not compatible. | Customer restart system, then monitor over a few days. If the system is continually showing the fault for approx 3 days request a maintenance service request. |
| 456 | Anto-islanding function is no longer implemented correctly | Customer restart system, then monitor over a few days. If the system is continually showing the fault for approx 3 days request a maintenance service request. |
| 457 | The grid relay sticking or the nuetral conductor ground voltage is too high | Send installer to site to check grounding. Neutral conductor ground voltage has to be less than 30V. Submit a maintenance service request. |
| 458-459 | Issues when recording the measuring signal | Restart the system. Check there are no firmware updates. Leave for 24 hours if the fault still persists submit a maintenance service request. |
| 460 | Reference voltage source for the DSP is working out of tolerance | Restart the system. Check there are no firmware updates. Leave for 24 hours if the fault still persists submit a maintenance service request. |
| 461 | Error with DSP data memory | Restart the system. Check there are no firmware updates. Leave for 24 hours if the fault still persists submit a maintenance service request. |
| 462 | Fault with the DC feed monitoring routine | Restart the system. Check there are no firmware updates. Leave for 24 hours if the fault still persists submit a maintenance service request. |
| 463 | Reversed AC Polarity | The AC connector has been incorrectly inserted. This should not occur unless the customer has been fiddling with the system or they have had works done onsite and another technician has touched/changed the install. Submit a maintenance service request. |
| 474 | RCMU sensor is faulty | Submit a maintenance service request. |
| 475 | Insulation fault. The connection between the solar panel and ground is faulty | Submit a maintenance service request. |
| 476 | The driver supply voltage is too low | Restart system, if still present, submit a maintenance service request. |
| 479 | Immediate circuit relay has switched off | Restart system, if still present after an hour or two, submit a maintenance service request. |
| 480-481 | Inverter firmware need to be updated. This needs to be done with enough daylight for whole update or the inverter will need to be replaced with likely no warranty. Submit a maintenance service request. | Restart system, if still present after an hour or two, submit a maintenance service request. |
| 482 | The setup phase after initial startup was interupted | Full system restart required. Turn of AC circuit breaker, after 5 minutes turn back on, then after another 5-10 minutes restart the system. Complete during daylight hours. |
| 483 | The voltage UDC fixed on MPP2 string is out of limit | Send installer to site to check MPP settings. If correct and persisting, complete full restart including AC circuit breaker, if still persisting contact Fronius. Submit a maintenance request. |
| 485 | CAN transmit buffer is full | Conduct AC reset (turn off, wait 5 minutes and turn on again) |
| 489 | Permanent intermediate circuit capacitor over voltage | Submit a maintenance service request. |
| 502 | Insulation fault on the solar panels | Generally will correct itself within a few hours. If not, restart the system. If code stays on for a prolonged period submit a maintenance service request. |
| 509 | No energy has been fed into the grid in the last 24 hours | Ensure no power outages in the area. If persistent for 2 days or more submit a maintenance service request. |
| 515 | Unable to communicate with filter | Generally will correct itself within a few hours. If not, restart the system. If code stays on for a prolonged period submit a maintenance service request. |
| 516 | Unable to communicate with the storage unit | Generally will correct itself within a few hours. If not, restart the system. If code stays on for a prolonged period submit a maintenance service request. |
| 517 | No energy has been fed into the grid by MPPT 1 in the past 24 hours | Check nothing is blocking inverter air openings, if blocked, remove as these need to be clear. The fault should clear within 5 minutes but if not, restart the system. If the fault is still persistent, inverter may need to be replaced. Submit a maintenance service request. |
| 518 | Internal DSP fault | Check nothing is blocking inverter air openings, if blocked, remove as these need to be clear. The fault should clear within 5 minutes but if not, restart the system. If the fault is still persistent, inverter may need to be replaced. Submit a maintenance service request. |
| 519 | Unable to communicate with storage unit | Check nothing is blocking inverter air openings, if blocked, remove as these need to be clear. The fault should clear within 5 minutes but if not, restart the system. If the fault is still persistent, inverter may need to be replaced. Submit a maintenance service request. |
| 520 | No energy has been fed into the grid by MPPT 1 in the past 24 hours | Check nothing is blocking inverter air openings, if blocked, remove as these need to be clear. The fault should clear within 5 minutes but if not, restart the system. If the fault is still persistent, inverter may need to be replaced. Submit a maintenance service request. |
| 522 | DC is low in string 1 | Check nothing is blocking inverter air openings, if blocked, remove as these need to be clear. The fault should clear within 5 minutes but if not, restart the system. If the fault is still persistent, inverter may need to be replaced. Submit a maintenance service request. |
| 523 | DC is low in string 2 | Check nothing is blocking inverter air openings, if blocked, remove as these need to be clear. The fault should clear within 5 minutes but if not, restart the system. If the fault is still persistent, inverter may need to be replaced. Submit a maintenance service request. |
| 528-529 | There is a functional incompatibility (one or more of the PC boards are not compatible) | Inverter firmware needs to be updated. This needs to be done with enough daylight for whole update or the inverter will need to be replaced with likely no warranty. |
| 560 | Grid frequency has become excessively high which is causing derating | Fault will fix itself, only requires attention if the fault occurs for a prolonged period of time. |
| 564 | See error 528-529 | |
| 566 | Arc Detector has been deactivated | Press enter (4th button from the left) wait 5 minutes and error should be clear. |
| 567 | The GVDPR is active and inverter will operate with reduced power output | System is still working but at slightly reduced power, code should clear itself within a few hours. If not submit a maintenance service request. |
| 601 | CAN bus is full | Inverter firmware needs to be updated. This needs to be done with enough daylight for whole update or the inverter will need to be replaced with likely no warranty. |
| 603 | AC module sensor is faulty | Restart system, if still present submit a maintenance service request. |
| 604 | DC module sensor is faulty | Restart system, if still present submit a maintenance service request. |
| 607 | RCMU Fault | Press enter (4th button from the left) wait 5 minutes and error should be cleared. |
| 608 | See error 528-529 | |
| 609 | Configuration value out of limits | Submit a maintenance service request. |
| 701-730 | Information about the internal processors status | Fault should clear itself within a few hours. If persistent, restart the system. If problem still not resolved submit a maintenance service request. |
| 721 | EEPROM has been reinstalled | Fault should clear itself within a few hours. If persistent, restart the system. If problem still not resolved submit a maintenance service request. |
| 722-730 | Information about the internal processors status | Fault should clear itself within a few hours. If persistent, restart the system. If problem still not resolved submit a maintenance service request. |
| 731 | USB flash drive not supported | Check the USB flash drive and files, may need to be replaced. Submit a maintenance service request. |
| 732 | Initialisation error with USB flash drive | Check the USB flash drive and files, may need to be replaced. Submit a maintenance service request. |
| 733 | USB flash drive not connected | Check the USB flash drive and files, may need to be replaced. Submit a maintenance service request. |
| 734 | Update file missing or not recognised | Check for updates to Firmware. Run update if required and fault should be cleared. If not, restart the system and if the error still occurs submit a maintenance service request. |
| 735 | Update file too old | Contact Fronius to check USB drive and files, may need to be replaced. Have photos of code and inverter serial handy for call. Submit a maintenance service request. |
| 736 | Write or read error | Contact Fronius to check USB drive and files, may need to be replaced. Have photos of code and inverter serial handy for call. Submit a maintenance service request. |
| 737 | Unable to open file | Contact Fronius to check USB drive and files, may need to be replaced. Have photos of code and inverter serial handy for call. Submit a maintenance service request. |
| 738 | Unable to save log file | Contact Fronius to check USB drive and files, may need to be replaced. Have photos of code and inverter serial handy for call. Submit a maintenance service request. |
| 740 | Error in file system | Contact Fronius to check USB drive and files, may need to be replaced. Have photos of code and inverter serial handy for call. Submit a maintenance service request. |
| 741 | Error recording logging data | Contact Fronius to check USB drive and files, may need to be replaced. Have photos of code and inverter serial handy for call. Submit a maintenance service request. |
| 743 | Error during update | Contact Fronius |
| 745 | Update file corrupt | Contact Fronius |
| 746 | Error while updating | Contact Fronius |
| 751 | Time lost | Time and date on inverter needs to be reset. Submit a maintenance service request. |
| 752 | Communication error with real time clock module | Time and date on inverter needs to be reset. Submit a maintenance service request. |
| 753 | Real time clock module is in emergency mode | Time and date on inverter needs to be reset. Submit a maintenance service request. |
| 754-755 | Information about the processors status | Fronius needs to be contacted, generally they will want an installer onsite but can try without if the code is persistent. |
| 757 | Real time clock module hardware error | Fronius needs to be contacted, generally they will want an installer onsite but can try without if the code is persistent. |
| 758 | Real time clock module is in emergency mode | Time and date on on inverter needs to be reset. If code does not clear instantly restart the system. |
| 760 | Internal hardware fault | Submit a maintenance service request. |
| 761-765 & 767 | Information about internal processors status | Submit a maintenance service request. |
| 766-733 | Emergency power derating has triggered | Restart inverter, if problem persists submit a maintenance service request. |
| 775 | PMC power stage set unavailable | Press enter on the inverter (4th button from left). If problem still persists contact Fronius. |
| 776 | Device type invalid | Press enter on the inverter (4th button from left). If problem still persists contact Fronius. |
| 779 | CAN bus transmission error | Contact Fronius. |
| 781-794 | Information about internal processors status | Contact Fronius. |
Why Powermate?
At Powermate, we specialise in keeping your solar system running efficiently. Our team is experienced in diagnosing and resolving inverter issues, ensuring your system performs at its best.
Need Assistance?
If your Fronius inverter displays a code you don’t understand or one that persists, please submit a maintenance request here. If you require the manufactures guide you can access this via fronius. Our friendly experts can provide the solutions you need to maintain a reliable and safe solar system. If you need an easy guide to setting up Wi-Fi on your Fronius inverter click here.
