Your Growatt inverter is displaying a code and you want to know what it means. This page covers every documented Growatt error code and warning code across three generations of hardware: the original Gen 1 grey inverters, the Gen 2 white string inverters, and the current XH hybrid range including the MIN XH, MIN XH2, MOD XH and MID XH.
Each code is listed with a plain-language description and the recommended action. Some actions you can safely do yourself. Others require a licensed solar electrician. The distinction matters, and we have been explicit about it throughout.
How to use this page: identify your inverter generation (grey, white or hybrid), then find your code in the relevant section. If you are unsure which generation you have, the colour of the inverter casing is the simplest identifier. Grey housing is Gen 1. White housing is Gen 2 or XH hybrid.
Contents
Gen 1: warning codes (grey inverters)
Older Growatt inverters in the grey housing display warning codes rather than error codes. A warning (W followed by a number) identifies the inverter’s current status. Warnings do not always indicate a fault. Many are cleared through a standard shutdown and restart, or by the inverter’s own corrective actions.
These units are no longer in production, but they remain in service across thousands of Australian rooftops. If your grey Growatt is still generating after 8–10 years, it has done well. The codes below will help you keep it running.
| Code | Description | What to do |
|---|---|---|
W01 | Fan fault | Open the inverter and check whether the fan is operating. Reseat or replace the fan connector. If the fan itself has failed, it will need replacing. Contact your solar installer. |
W02 | Internal temperature high | Check that the inverter has adequate ventilation clearance (minimum 300mm sides, 500mm top and bottom). Remove any obstructions or debris from heat sink fins. If installed in direct sunlight, consider shade screening. Restart the inverter. If the warning persists, contact your solar installer. |
W03 | Battery voltage high | For lithium batteries: confirm the battery communicates normally with the inverter. If the warning persists with normal communication, contact the battery manufacturer for a firmware update. For lead-acid batteries: check the bulk and float charging voltage settings (options 19 and 20 on the LCD). |
W04 | Battery voltage/SoC too low | Disconnect the battery breaker and measure the actual battery voltage with a multimeter. Compare with the voltage displayed on the inverter LCD. If there is a large difference, calibrate via the inverter settings. If the battery has discharged below its safe cut-off, it may need to recover before the inverter can restart. |
W05 | PV isolation low | The solar array may have insufficient insulation to ground. This is common after heavy rain or if panel frames are not properly earthed. A licensed electrician should test string insulation resistance. Do not attempt to inspect DC wiring yourself. |
W06 | String current high | After shutdown, check each string for correct panel count and wiring. Look for bypass diode failures or short circuits within the array. Contact your solar installer. |
W07 | String voltage high | The DC input voltage from the panels is approaching or exceeding the inverter maximum. This can occur in cold weather when panel voltage rises. After shutdown, measure the open circuit voltage of each string. If it exceeds the inverter maximum input, the string configuration needs adjustment by your installer. |
W09 | Boost module error | Restart the inverter. If the warning persists, contact your solar installer. |
W10 | NTC temperature too high or NTC broken | Restart the inverter. If the warning persists, the NTC temperature sensor on the MPPT board or mainboard may need replacing. Contact your solar installer. |
W11 | NTC broken | Restart the inverter. If the warning persists, the temperature sensor requires replacement. Contact your solar installer. |
W13 | CT connect abnormal | Restart the inverter. Check the current transformer (CT) clamp connections. If the warning persists, contact your solar installer. |
W14 | AFCI fault (arc-fault circuit interrupter) | After shutdown, inspect all PV panel terminals and DC cable connections for damage, corrosion or loose contacts. Reset the inverter. If the warning keeps appearing, a licensed solar electrician should test each string for arc fault conditions. |
W15 | USB over-current | Unplug the USB stick or monitoring device. After shutdown, reconnect the device. If the warning persists, the USB port or device may be faulty. Contact your solar installer. |
W16 | DC fuse open | After shutdown, check the internal DC fuse. A blown fuse typically indicates a wiring fault on the DC side. Contact your solar installer. |
W17 | DC input voltage exceeding maximum tolerable value | Immediately disconnect the DC switch. Measure |
W18 | PV reversed | Check the PV input terminal polarity. Positive and negative cables may be swapped on one or more strings. Correct the wiring. This must be done by a qualified installer with the DC side isolated. |
W19 | AC SPD function abnormal | After shutdown, check the AC surge protection device (SPD). The SPD indicator may show a trip. If the SPD has operated, it may need replacement. Contact your solar installer. |
W20 | BMS communication error | The battery management system cannot communicate with the inverter. Replace or reseat the BMS communication cable. Check the Growatt compatibility list for your battery. If the battery is not on the list, set battery type to US2 in inverter setting option 5 to operate without BMS communication. |
W21 | String PID quick connect terminal detection error | After shutdown, check the string terminal wiring for the PID (potential induced degradation) module. Contact your solar installer. |
W22 | String fault | After shutdown, check the PV panels and string wiring are normal. Inspect for broken connectors, damaged cables or panel faults. If the |
Gen 2: error codes (white inverters)
The Gen 2 white-cased Growatt inverters (MIN, MOD, MID and MAX series) use three-digit error codes grouped by fault type. This is the fastest way to narrow down the problem:
1xx and 4xx: Internal hardware or system faults. These rarely respond to a simple restart and often require professional servicing.
2xx: PV/DC side faults. Related to the solar panels, DC cabling, insulation, or arc detection.
3xx: AC grid side faults. Related to the grid connection, voltage, frequency, or AC wiring.
Hardware and system faults (1xx)
Error codes in the 1xx range typically indicate a physical failure of internal components: the control board, EEPROM memory, current sensors or communication links between internal processors. A simple restart will occasionally clear these codes, but persistent 1xx errors usually require boardlevel repair or component replacement.
| Code | Description | What to do |
|---|---|---|
101 | Communication fault between main board and control panel | Turn off the DC switch and allow the inverter to shut down completely. Turn the DC switch back on. If the error persists, the communication link between internal boards may be damaged. Contact your solar installer. |
102 | Data mismatch between master and slave processors | Follow the same steps as Error 101. If unresolved, the control board may need servicing. Contact your solar installer. |
103 | EEPROM read/write failure | If this error only appears briefly at sunrise and clears when production begins, it is typically harmless. If it persists throughout the day, restart the inverter. A persistent EEPROM fault may indicate the control board needs replacement. Contact your solar installer. |
104 | Communication fault (internal) | Restart the inverter. If the error persists, contact your solar installer. |
105 | DSP communication error | Restart the inverter. If the error persists, contact your solar installer. |
106 | Firmware version mismatch | The main board and communication board may be running incompatible firmware. Contact Growatt support or your solar installer to arrange a firmware update. |
107 | GFCI test failure | Restart the inverter. If the error persists, the ground fault circuit interrupter module may need servicing. Contact your solar installer. |
108 | SPI communication error | Restart the inverter. If the error persists, contact your solar installer. |
109 | This suggests a hardware fault in the AC relay. Do not attempt to reset repeatedly. Contact your solar installer for relay inspection and replacement. | Restart the inverter. If the warning persists, the NTC temperature sensor on the MPPT board or mainboard may need replacing. Contact your solar installer. |
110 | DSP program exception | Restart the inverter. If the error persists, contact your solar installer. |
117 | 12V power supply failure | The internal low-voltage supply has failed. This typically requires board-level repair. Contact your solar installer. |
120 | <strong>W20</strong><strong>W20</strong>Current sensor error | Restart the inverter. If the error persists, the current sensor on the main board may need replacement. Contact your solar installer. |
121 | Sampling error | Restart the inverter. If the error persists, contact your solar installer. |
PV and DC side faults (2xx)
These codes relate to the DC input from the solar panels. They cover arc faults, insulation issues, leakage current, and overvoltage conditions.
Safety: Error 200 (AFCI) and Error 202 (DC overvoltage) are safety-critical codes. Do not attempt to override the shutdown. Disconnect the DC switch and seek professional assistance.
| Code | Description | What to do |
|---|---|---|
200 | AFCI fault (arcfault circuit interrupter) | The inverter has detected a potential electrical arc in the PV system and has shut down permanently as a safety measure. Do not attempt to override this shutdown. Turn off the DC and AC switches. Wait for the display to go off. Check all PV string connections for damage, corrosion, loose terminals or cracked insulation. Check the open circuit voltage of each string is within normal range. After the fault is rectified, turn the DC and AC switches back on. If the error recurs, a licensed solar electrician must inspect the DC wiring. For MIN XH2 models: AFCI cannot be permanently deactivated. If parallel-wired MPPTs are causing false trips, the DC wiring configuration may need correcting. |
201 | Leakage current too high / residual current fault | The inverter has detected a residual current exceeding safe thresholds. This may indicate a ground fault in the PV array, moisture ingress into a junction box, or damaged cable insulation. Restart the inverter. If the error persists, a licensed electrician must test the array insulation resistance. Do not operate the system until the fault is located and repaired. |
202 | DC input voltage exceeding maximum tolerable value | Immediately disconnect the DC switch. Do not touch any DC cabling. Measure the open circuit voltage of each PV string with a multimeter. If voltage exceeds the inverter maximum input specification, the string has too many panels in series and the configuration needs correcting by a qualified installer. |
203 | PV insulation low / isolation fault | The PV array insulation resistance to earth is below the safe threshold. After shutdown, check that panel frames and mounting rails are properly earthed. Inspect for damaged cables, cracked panels or moisture in junction boxes. A licensed electrician should perform megger testing on each string. Do not reconnect until insulation resistance is confirmed safe. |
204 | DC injection too high | The inverter is injecting too much DC current into the AC output. Restart the inverter. If the error persists, the DC component may indicate an internal fault. Contact your solar installer. |
205 | Output current DC offset too high | Restart the inverter. If the error persists, contact your solar installer. |
AC grid side faults (3xx)
These codes relate to the AC grid connection. In Western Australia on the SWIS grid, the most common 3xx code is Error 300 (grid voltage out of range). This frequently occurs in suburbs with high rooftop solar penetration, where network voltage rises during peak generation hours. It is usually a network issue, not an inverter fault.
WA-specific note: If you experience frequent Error 300 events, contact Western Power (the network operator, not Synergy) to request a voltage investigation at your property. Your solar installer can also apply to adjust the inverter’s voltage trip settings within the limits permitted by AS/NZS 4777.2.
| Code | Description | What to do |
|---|---|---|
300 | Grid voltage out of range | The AC grid voltage at your property is outside the inverter’s programmed limits. This is common in areas with high solar penetration, particularly during the middle of the day when network voltage rises. The inverter will automatically restart within five minutes if voltage returns to the acceptable range. If this happens frequently, contact Western Power (in the Perth metro area) or your network operator to request a voltage investigation at your property. Your solar installer can also adjust the voltage trip settings if permitted under AS/NZS 4777.2. |
301 | AC terminals inverted / phase error | The AC line and neutral connections at the inverter are reversed. After shutdown, a licensed electrician should check the AC wiring at the inverter terminals and the switchboard. Do not operate the inverter with reversed AC polarity. |
302 | No AC connection | The inverter cannot detect an AC grid connection. Check that the AC circuit breaker for the solar system is switched on. If the breaker has tripped, there may be an underlying fault. If the breaker is on and the error persists, check for a grid outage in your area. Contact your solar installer if the AC supply is confirmed but the error remains. |
303 | Neutral-earth (NE) abnormal | The PE (protective earth) line may not be making proper contact. Check that the earth connection at the inverter and switchboard is secure. If the error persists, a licensed electrician should test the earthing system. This can also occur if the neutralearth link has been disturbed at the switchboard. |
304 | AC frequency out of range | The grid frequency has drifted outside the inverter’s programmed limits. This is typically a network issue and will self-correct. If the error persists, contact your solar installer. In WA on the SWIS grid, frequency excursions are relatively rare but can occur during network disturbances. |
305 | Overload error | The output load connected to the inverter exceeds its rated capacity. This applies primarily to hybrid inverters running in backup mode. Reduce the load by switching off high-draw appliances. If the load is within the inverter’s rated output and the error persists, contact your solar installer. |
306 | CT line-neutral reversed (hybrid models) | The current transformer (CT) clamp is installed with the line and neutral reversed. After shutdown, check the SP-CT connection orientation. The CT must be installed with the correct directional arrow pointing from grid to load. This is an installation correction, not a fault. |
307 | Communication error: M3 did not receive SP-CT data (hybrid models) | The communication cable between the CT and the inverter is disconnected, damaged or not properly seated. Check the cable and reseat both ends. If the error persists, the cable may need replacing. Contact your solar installer. |
Hardware, relay and sensor faults (4xx)
Error codes in the 4xx range cover DC bus faults, relay failures, temperature sensor issues and sampling errors. Error 405 (relay error) is the most commonly reported in this group. Persistent 4xx errors typically indicate hardware wear and require a service visit.
| Code | Description | What to do |
|---|---|---|
400 | DC bus overload | Restart the inverter. If the error persists, the DC bus capacitors or associated circuitry may need servicing. Contact your solar installer. |
401 | DC high voltage fault | Restart the inverter. If the error persists, contact your solar installer. |
402 | Current too high (internal) | Restart the inverter. If the error persists, contact your solar installer. |
403 | Unbalanced output current (three-phase models) | After shutdown, check whether the load across the three phases is significantly unbalanced. If the loads are reasonably balanced and the error persists, contact your solar installer. |
404 | <strong>120</strong>Bus sampling error | Restart the inverter. If the error persists, contact your solar installer. |
405 | Relay error | The internal AC relay has failed to operate correctly. This can indicate relay wear, particularly on older units. Restart the inverter. If the error persists, the relay likely needs replacement. Contact your solar installer. Do not repeatedly attempt to restart, as a faulty relay can cause arcing |
406 | Initialisation error | Restart the inverter. If the error persists, contact your solar installer |
407 | Self-test error / automatic test sequence failed | Restart the inverter. The fault should clear. If it persists after two restarts, contact your solar installer. |
408 | NTC temperature too high | The internal temperature sensor has detected excessive heat. After shutdown, check that the inverter has adequate ventilation clearance and that the heat sink fins are clean. Allow the inverter to cool before restarting. If the error persists in a well-ventilated installation, the temperature sensor or thermal management system may need servicing. |
409 | Invalid bus voltage | Restart the inverter. If the error persists, contact your solar installer. |
410 | Supply voltage | Restart the inverter. If the error persists, contact your solar installer. |
411 | PV voltage too low / communication error (model dependent) | For standard grid-tie inverters: check PV connections for poor contact and verify PV voltage is within the required range. For MIN XH or MOD XH with ARK XH battery: follow this restart sequence: turn off battery, turn off DC switch, turn off AC side. Then start battery, turn on DC switch, turn on AC side. If the error persists, contact your solar installer. |
412 | Temperature sensor connection incorrect | After shutdown, check that the temperature sampling module is properly connected and seated. If the error persists, contact your solar installer. |
413 | Grid relay fault | Restart the inverter. If the error persists, the grid relay may need replacement. Contact your solar installer. |
418 | Internal hardware fault | This is a persistent hardware fault that typically requires board-level repair. Contact your solar installer or Growatt support directly. |
423 | <strong>120</strong>IGBT fault | An insulated-gate bipolar transistor has failed. This is a hardware fault requiring professional repair. Contact your solar installer. |
424 | Bus voltage sampling fault | <strong>120</strong>Restart the inverter. If the error persists, contact your solar installer. |
425 | Output current sampling fault | Restart the inverter. If the error persists, contact your solar installer. |
426 | Boost current | Restart the inverter. If the error persists, contact your solar installer. |
427 | PV voltage sampling | Restart the inverter. If the error persists, contact your solar installer. |
428 | Output voltage sampling fault | Restart the inverter. If the error persists, contact your solar installer. |
Hybrid inverters: battery and backup codes (XH series)
Growatt’s XH hybrid inverters (MIN XH, MIN XH2, MOD XH, MID XH) produce the same Gen 2 error codes listed above, plus additional codes related to battery communication, backup operation and CT metering. If your XH inverter displays a standard 1xx–4xx code, refer to the Gen 2 tables. The codes below are specific to hybrid operation.
Which inverters does this section cover? MIN 2500–6000TL-XH, MIN 2500– 6000TL-XH2, MOD 3–10KTL3-XH, MOD 3–11KTL3-XH-AU, and MID 11–30KTL3XH. These models pair with Growatt ARK XH (low voltage) and APX HV (high voltage) battery systems.
AFCI on XH2 models
The MIN XH2 series includes integrated AFCI (arc fault circuit interrupter) protection as standard. When Error 200 is triggered, the buzzer will sound and the inverter enters a permanent shutdown state. This is a safety response to a detected electrical arc in the PV system.
Safety: Do not deactivate the AFCI permanently. Do not attempt to override the safety shutdown. Disconnect all power supplies and have a licensed solar electrician inspect the DC wiring before restarting.
If parallel-wired MPPTs are causing false AFCI trips, the DC wiring configuration may need correcting. The XH2 is designed with dual MPPTs operating independently. Parallel wiring on the DC side can cause the two MPPTs to interfere, triggering a false arc detection.
Battery and backup fault codes
| Code | Description | What to do |
|---|---|---|
W03 | Battery voltage high | For lithium batteries with BMS: confirm BMS communication is active. Contact the battery manufacturer for firmware compatibility. For leadacid: check bulk and float voltage settings. If the battery was not purchased from Growatt or is not on the compatibility list, set battery type to US2 in setting option 5. |
W04 | Battery voltage/SoC too low | Disconnect the battery breaker and measure actual battery voltage with a multimeter. Compare to the LCD reading. If the battery has discharged below safe limits, it may need time to recover before the inverter can restart. For lithium batteries that have entered deep sleep, consult the battery manufacturer for the wake procedure. |
W19 | AC SPD abnormal | Check the AC surge protection device for a trip indicator. If operated, the SPD module may need replacement. Contact your solar installer. |
W20 | BMS communication error | The battery management system is not communicating with the inverter. Check the BMS cable connection at both ends. Verify the battery brand is on the Growatt compatibility list. If not listed, set battery type to US2 in option 5 and max charge current under 30A in option 2 for single battery setups. |
305 | Overload (backup mode) | The load connected during a grid outage exceeds the inverter backup capacity. Reduce load by switching off high-draw appliances (electric ovens, pool pumps, large air conditioners). The inverter will restart automatically once the load drops below its rated backup output. |
306 | CT line-neutral reversed | The SP-CT current transformer clamp is installed in the wrong orientation. The directional arrow must point from grid to load. This is an installation correction. Contact your solar installer. |
307 | SP-CT communication failure | The communication cable between the CT clamp and inverter is disconnected or damaged. Check and reseat both ends of the cable. Replace if damaged. |
411 | PV voltage too low / hybrid communication fault | For XH systems with ARK XH battery: follow this restart sequence: (1) turn off battery, (2) turn off DC switch, (3) turn off AC. Then: (1) start battery, (2) turn on DC switch, (3) turn on AC. If the error persists, contact your solar installer. |
Hybrid restart sequence
For persistent faults on XH systems with ARK XH or APX batteries, follow this shutdown and restart sequence in order:
- Shutdown: (1) Turn off the battery. (2) Turn off the DC switch on the inverter. (3) Turn off the AC breaker.
- Restart: (1) Turn on the battery. (2) Turn on the DC switch. (3) Turn on the AC breaker
This sequence ensures the battery, DC input and AC grid reconnect in the correct order, which avoids communication timeouts between the inverter and battery management system.
When to call a professional
Some of the actions above are safe for any homeowner or business operator to perform: checking that a circuit breaker is on, verifying ventilation clearance, cleaning dust from heat sink fins, or restarting the inverter via the DC and AC switches.
These actions require a licensed solar electrician or your installation company:
- Any work on DC cabling, connectors or junction boxes
- Measuring string voltages (DC systems carry lethal voltages)
- Investigating insulation resistance or earth faults
- Replacing internal components (relays, sensors, fans, fuses)
- Adjusting inverter voltage or frequency trip settings
- Any work inside the inverter enclosure
If your inverter was installed by PSW Energy or Perth Solar Warehouse, contact PSW Life Support for assistance. For persistent error codes on systems installed by other companies, contact your original installation company first. They hold the commissioning records and warranty relationship.
