Fault code 01 shown on the display with the fault icon on: Fan is locked when inverter is off..
CauseFan fault.
Recommended fixReplace the fan.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 44Axpert-MKS-IV-TWIN-manual.pdf· page 50
Voltronic Axpert MKS IV TWIN Error Codes: Causes & Fixes (34 codes)
This is the complete fault table for the Voltronic Axpert MKS IV TWIN Inverter — all 34 codes from the official manual on one page. On Voltronic units, a fault code means the unit has cut its output and the red LED stays solid; a warning flashes the red LED while the unit keeps running.
Last checked against the official manuals on July 27, 2026.
How to read the severity labels
- Fault(27)— output stops · red LED solid
- Warning(7)— unit keeps running · red LED flashing
Fault codes (27)output stops · red LED solid
Fault code 02 shown on the display with the fault icon on: Over temperature.
CauseInternal temperature of inverter component is over 100°C.
Recommended fixCheck whether the air flow of the unit is blocked or whether the ambient temperature is too high.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 44Axpert-MKS-IV-TWIN-manual.pdf· page 50
Fault code 03 shown on the display with the fault icon on: Battery voltage is too high.
CauseBattery is over-charged.
Recommended fixReturn to repair center.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 44Axpert-MKS-IV-TWIN-manual.pdf· page 50
Fault code 05 shown on the display with the fault icon on: Output short circuited..
CauseOutput short circuited.
Recommended fixCheck if wiring is connected well and remove abnormal load.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 44Axpert-MKS-IV-TWIN-manual.pdf· page 50
Fault code 06 shown on the display with the fault icon on: Output voltage is too high..
CauseOutput abnormal (Inverter voltage below than 190Vac or is higher than 260Vac).
Recommended fix1. Reduce the connected load. 2. Return to repair center.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 44Axpert-MKS-IV-TWIN-manual.pdf· page 50
Fault code 07 shown on the display with the fault icon on: Overload time out.
CauseOverload error. The inverter is overload 110% and time is up.
Recommended fixReduce the connected load by switching off some equipment.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 44Axpert-MKS-IV-TWIN-manual.pdf· page 50
Fault code 08 shown on the display with the fault icon on: Bus voltage is too high.
CauseInternal components failed.
Recommended fixReturn to repair center.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 44Axpert-MKS-IV-TWIN-manual.pdf· page 50
Fault code 09 shown on the display with the fault icon on: Bus soft start failed.
CauseInternal components failed.
Recommended fixReturn to repair center.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 44Axpert-MKS-IV-TWIN-manual.pdf· page 50
Fault code 10 shown on the display with the fault icon on: PV over current.
CausePV over current.
Recommended fixRestart the unit. If the fault happens again, contact your installer or the repair centre.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 44
Fault code 11 shown on the display with the fault icon on: PV over voltage.
CausePV over voltage.
Recommended fixRestart the unit. If the fault happens again, contact your installer or the repair centre.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 44
Fault code 12 shown on the display with the fault icon on: DCDC over current.
CauseDCDC over current.
Recommended fixRestart the unit. If the fault happens again, contact your installer or the repair centre.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 44
Fault code 51 shown on the display with the fault icon on: Over current.
CauseOver current or surge.
Recommended fixRestart the unit, if the error happens again, please return to repair center.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 44Axpert-MKS-IV-TWIN-manual.pdf· page 50
Fault code 52 shown on the display with the fault icon on: Bus voltage is too low.
CauseBus voltage is too low.
Recommended fixIf the battery is connected well, please return to repair center.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 44Axpert-MKS-IV-TWIN-manual.pdf· page 50
Fault code 53 shown on the display with the fault icon on: Inverter soft start failed.
CauseInternal components failed.
Recommended fixReturn to repair center.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 45Axpert-MKS-IV-TWIN-manual.pdf· page 50
Fault code 55 shown on the display with the fault icon on: Over DC voltage in AC output.
CauseOutput voltage is unbalanced.
Recommended fixIf the battery is connected well, please return to repair center.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 45Axpert-MKS-IV-TWIN-manual.pdf· page 50
Fault code 57 shown on the display with the fault icon on: Current sensor failed.
CauseInternal components failed.
Recommended fixReturn to repair center.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 45Axpert-MKS-IV-TWIN-manual.pdf· page 50
Fault code 58 shown on the display with the fault icon on: Output voltage is too low.
CauseOutput abnormal (Inverter voltage below than 190Vac or is higher than 260Vac).
Recommended fix1. Reduce the connected load. 2. Return to repair center.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 45Axpert-MKS-IV-TWIN-manual.pdf· page 50
Fault code 60 shown on the display with the fault icon on: Power feedback protection.
CausePower feedback protection.
Recommended fixRestart the unit. If the fault happens again, contact your installer or the repair centre.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 65
Fault code 71 shown on the display with the fault icon on: Firmware version inconsistent.
CauseFirmware version inconsistent.
Recommended fixRestart the unit. If the fault happens again, contact your installer or the repair centre.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 65
Fault code 72 shown on the display with the fault icon on: Current sharing fault.
CauseCurrent sharing fault.
Recommended fixRestart the unit. If the fault happens again, contact your installer or the repair centre.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 65
Fault code 80 shown on the display with the fault icon on: CAN fault.
CauseCAN fault.
Recommended fixRestart the unit. If the fault happens again, contact your installer or the repair centre.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 65
Fault code 81 shown on the display with the fault icon on: Host loss.
CauseHost loss.
Recommended fixRestart the unit. If the fault happens again, contact your installer or the repair centre.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 65
Fault code 82 shown on the display with the fault icon on: Synchronization loss.
CauseSynchronization loss.
Recommended fixRestart the unit. If the fault happens again, contact your installer or the repair centre.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 65
Fault code 83 shown on the display with the fault icon on: Battery voltage detected different.
CauseBattery voltage detected different.
Recommended fixRestart the unit. If the fault happens again, contact your installer or the repair centre.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 65
Fault code 84 shown on the display with the fault icon on: AC input voltage and frequency detected different.
CauseAC input voltage and frequency detected different.
Recommended fixRestart the unit. If the fault happens again, contact your installer or the repair centre.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 65
Fault code 85 shown on the display with the fault icon on: AC output current unbalance.
CauseAC output current unbalance.
Recommended fixRestart the unit. If the fault happens again, contact your installer or the repair centre.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 65
Fault code 86 shown on the display with the fault icon on: AC output mode setting is different.
CauseAC output mode setting is different.
Recommended fixRestart the unit. If the fault happens again, contact your installer or the repair centre.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 65
Warning codes (7)unit keeps running · red LED flashing
Warning code 01 flashing on the display: Fan is locked when inverter is on.. Audible alarm: beep three times every second.
CauseFan is locked when inverter is on.
Recommended fixReplace the fan.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 45
Warning code 02 flashing on the display: Over temperature.
CauseOver temperature.
Recommended fixCheck whether the air flow of the unit is blocked or whether the ambient temperature is too high.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 45
Warning code 03 flashing on the display: Battery is over-charged. Audible alarm: beep once every second.
CauseBattery is over-charged.
Recommended fixReturn to repair center.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 45
Warning code 04 flashing on the display: Low battery. Audible alarm: beep once every second.
CauseLow battery.
Recommended fixThe unit keeps operating. Clear the condition shown and the warning resets automatically; if it persists, contact your installer or the repair centre.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 45
Warning code 07 flashing on the display: Overload. Audible alarm: beep once every 0.5 second.
CauseOverload.
Recommended fixReduce the connected load by switching off some equipment.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 45
Warning code 10 flashing on the display: Output power is derated. Audible alarm: beep twice every 3 seconds.
CauseOutput power is derated.
Recommended fixThe unit keeps operating. Clear the condition shown and the warning resets automatically; if it persists, contact your installer or the repair centre.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 45
Warning code 32 flashing on the display: Communication failure between inverter and display panel.
CauseCommunication failure between inverter and display panel.
Recommended fixThe unit keeps operating. Clear the condition shown and the warning resets automatically; if it persists, contact your installer or the repair centre.
Source:Axpert-MKS-IV-TWIN-manual.pdf· page 45
Still seeing a code on your Axpert MKS IV TWIN?
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- All Voltronic error codesSearch every device and code in the database
- Voltronic & Axpert Error Codes by Model: Fault + Warning Code LookupThe step-by-step troubleshooting guide
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Common questions about Axpert MKS IV TWIN error codes
- What is the difference between a fault and a warning on the Axpert MKS IV TWIN?
- A fault cuts the unit's output and the red LED stays solid — this page lists 27 of them for the Axpert MKS IV TWIN. A warning only flashes the red LED and the unit keeps running; there are 7 warning codes here. Resolve the cause of a fault before restarting; warnings can usually be cleared while the unit runs.
- Does this page apply to other Voltronic models?
- No — this table was transcribed specifically from the Axpert MKS IV TWIN manual. Other Voltronic devices have their own pages; start from the error-code hub to find the one matching the model number on your unit's label.
- Where do these codes come from?
- Every entry was transcribed from Axpert-MKS-IV-TWIN-manual.pdf — Voltronic's official documentation. Each row cites its source manual (and page where printed), so you can verify the wording before acting on it.
Compiled from official Voltronic user manuals. Always consult your device manual and a qualified technician before performing repairs.