Is Your Fronius Inverter Displaying a Fault Code?
We are proud to have been Fronius Service Partners since 2011.
If your Fronius Inverter is displaying a fault code, our service specialists can provide you with assistance by consulting with Fronius and initiate the exchange of components for Fronius products.
To help us help you, you will need to supply us with the following information:
- The Fronius fault code displayed.
- The inverter model and number.
- The serial number.
- The purchase date to establish the warranty expiry date.
Please browse the table below for the specific fault code information your inverter may be displaying.

Code | Description | Possible Causes |
STATE 102 | Grid voltage beyond permitted limits |
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STATE 104 | Mains frequency beyond permitted limits |
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STATE 107 | Synchronisation with the public mains supply not possible |
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STATE 108 | Islanding detected |
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Code | Description | Possible Causes |
STATE 201 | Grid voltage is higher than the specified limit |
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STATE 202 | Grid voltage is lower than the specified limit | |
STATE 203 |
Grid frequency is higher than the specified limit |
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STATE 204 | Grid frequency is lower than the specified limit | |
STATE 205 | Change of public mains impedance |
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STATE 206 | Absolute value of the impedance is too high |
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STATE 207 |
Mains relay does not open in spite of switch-off signal |
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STATE 208 |
Mains relay does not close in spite of switch-on signal |
Code | Description | Possible Causes |
STATE 301 | Safety circuit detects a current peak on the mains supply |
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STATE 302 | Safety circuit detects a current peak on the PV generator side |
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STATE 303 | Heat sink temperature on the DC-AC board is too high |
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STATE 304 | Heat sink temperature on the DC-DC board is too high | |
STATE 305 | Feed-in process not possible, even though public mains parameter within the limits |
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STATE 306 | POWER LOW |
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STATE 307 | DC LOW |
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STATE 308 | Intermediate circuit voltage out of the maximum limit |
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Code | Description | Possible causes |
STATE 401 | Communication error between IG control and the DC-DC board |
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STATE 402 | Write access to the internal Fronius IG memory failed | |
STATE 403 | The area in the internal memory for the country setting is incomplete | |
STATE 404 | Connection between the control unit and the ENS is faulty |
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STATE 405 | An old or incorrect version of the ENS microprocessors has been recognised |
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STATE 406 | Temperature sensor on the DC-AC board faulty or not connected | |
STATE 407 | Temperature sensor on the DC-DC board faulty or not connected | |
STATE 408 | Unsymmetry on the public mains detected |
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STATE 409 | Supply of the DC-AC board not available |
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STATE 410 | Service plug on the DC-AC board is not set correctly | |
STATE 412 | Value for fixed voltage is set higher than the open circuit voltage of the PV generator | |
STATE 413 | Open circuit voltage too high in the moment of transformer switching | |
STATE 414 | Memory array for Fronius IG type in EE-PROM faulty |
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STATE 415 | No END-enabling signal despite release by IG-control |
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STATE 416 | Communication error between IG-Control and power stack |
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STATE 417 | Hardware ID-collision |
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STATE 419 | Two or more power stacks with identical Unique ID | |
STATE 420 | Incomplete number of power stacks detected after reaching online threshold according to device type | |
STATE 421 | Hardware ID sequence error | |
STATE 425 | Receive time-out for data exchange with one or more power stacks exceeded |
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STATE 431 | All power stacks are in boot mode |
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STATE 432 | Consistent error in power stack management |
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STATE 433 | Allocation error of dynamic addresses | |
STATE 434 | Ground fault detected | |
STATE 435 | Wrong configuration for EE-Prom | |
STATE 436 | Error transmission faulty | |
STATE 437 | Power stack work around is active | |
STATE 438 | Error during state code transmission |
|
STATE 441 | Power rack fan faulty |
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STATE 442 | Master for one phase could not be assigned |
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STATE 443 | DC-DC energy transfer failure |
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STATE 444 | AC monitoring self-test interrupted |
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If you are having difficulty with your Fronius Inverter, please contact us.
Our trained Solar Electrician’s can usually have your solar system up and running in one visit as we bring all the parts to your door. This is just one of the reasons we love being a Fronius Service Partner, they make it easy for you to continue generating energy from the sun again!
Add Your Heading Text Here
If you are having difficulty with your Fronius Inverter, please contact us.
Our trained Solar Electrician’s can usually have your solar system up and running in one visit as we bring all the parts to your door. This is just one of the reasons we love being a Fronius Service Partner, they make it easy for you to continue generating energy from the sun again!
Add Your Heading Text Here
Add Your Heading Text Here
If you are having difficulty with your Fronius Inverter, please contact us.
Our trained Solar Electrician’s can usually have your solar system up and running in one visit as we bring all the parts to your door. This is just one of the reasons we love being a Fronius Service Partner, they make it easy for you to continue generating energy from the sun again!