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Fault Code Finder

Search 426+ documented inverter and battery fault codes across 12 brands at once — then jump straight to the full entry, with what it means and what to do.

426 of 426 codes

		Fault	What it means
F08	Deye	GFDI relay failure	The inverter's ground-fault detection (GFDI) relay has failed a self-test, or the neutral/earth bonding doesn't match the configured grid type. On deployed firmware and rebadged (Sunsynk) units this is one of the most-reported codes and is very often a grid-type setting mismatch (e.g. set to 120/240V split-phase when the system is actually single-phase) rather than a true hardware fault. (Note: the current official Deye AU and EU manuals do NOT list an F08 - they number the equivalent start/ground self-check as F07. Confirm against your unit's firmware.)
F13	Deye	Working mode / grid mode changed	An informational event, not a hardware fault. The official manual logs it when the grid type or frequency setting changes, when the battery mode is switched to 'No battery', or (on some older firmware) when the system work mode changes. It normally clears itself.
F15	Deye	AC over-current (software)	The inverter's software protection has detected excessive current on the AC side (listed in the official manual as 'AC over current fault of software'). Can be triggered by a heavy backup or common load, or by an AC sensing issue.
F16	Deye	AC leakage current fault	The residual-current monitor has detected earth-leakage current above its threshold (official manual: 'AC leakage current fault'), which can indicate a PV array insulation problem or moisture in connectors. The manual's listed remedy focuses on the PV-side cable ground connection.
F18	Deye	AC over-current (hardware)	A hardware-level over-current trip on the AC side (official manual: 'AC over current fault of hardware'), typically from too much load on the backup and/or common-load outputs.
F20	Deye	DC over-current (hardware)	A hardware-level over-current trip on the DC side (PV or battery) - official manual: 'DC over current fault of the hardware'. Common when an off-grid/backup system is started into a large load, where inrush current briefly exceeds limits.
F22	Deye	Emergency stop / remote shutdown (Tz_EmergStop_Fault)	The inverter has been shut down by a remote-control or emergency-stop signal - it is being commanded off, not failing. The official manual states 'it tells the inverter is remotely controlled'.
F23	Deye	Transient leakage / GFCI over-current (Tz_GFCI_OC_Fault)	A transient earth-leakage (residual-current) over-current event, often linked to PV-side earthing. Confirmed in the official manual as 'Tz_GFCI_OC current is transient over current / leakage current fault'.
F24	Deye	DC insulation / isolation impedance failure	PV insulation resistance to earth is too low - the array's isolation impedance has dropped (official manual: 'DC insulation failure - PV isolation resistance is too low'), which can mean a damaged cable, water ingress, or a faulty panel/connector.
F26	Deye	DC busbar unbalanced	The internal DC busbar is unbalanced. The official manual notes it is logged when load across the phases is very uneven, and that it can also indicate DC leakage current.
F29	Deye	Parallel CAN bus fault	A communication fault on the parallel-link (CAN) bus between inverters in a multi-unit/parallel system. The official manual notes it is normal to see this briefly while a parallel system is powering up, and it clears once all units are ON.
F34	Deye	AC overload fault	The connected load exceeds what the inverter can supply (official manual: 'AC Overcurrent fault'), typically on the backup/EPS output. A common owner-facing code when too many appliances run at once on backup power.
F35	Deye	No AC grid (AC_NoUtility_Fault)	The inverter cannot detect a valid utility grid - i.e. the grid is absent or out of acceptable voltage/frequency range. Often simply a grid outage or a tripped supply breaker; on three-phase units it can also be caused by incorrect phase rotation/sequence. (Note: this F35 numbering is from deployed/Sunsynk firmware; the current official Deye manuals do not list an F35 - confirm against your unit.)
F41	Deye	Parallel system stop	In a parallel installation, one inverter has shut down, which causes the other paralleled inverters to report F41 and stop as a group (official manual: 'if there is 1 pcs hybrid inverter shutdown, all hybrid inverters will report F41').
F42	Deye	AC line low voltage	Measured grid (AC line) voltage is below the allowed range (official manual: 'AC line low voltage / grid voltage fault'). Frequently a grid-side condition (sagging supply) rather than an inverter fault.
F46	Deye	Backup battery fault	A fault with the connected battery (or batteries). The official Deye AU and EU manuals decode F46 as 'backup battery fault' and advise checking each battery's status - voltage, SOC and parameter settings - and making sure all parameters match. (Earlier third-party lists mislabelled F46 as 'AC under-voltage'; the decoded official manuals do not support that - treat F46 as a battery fault.)
F47	Deye	AC over-frequency	Grid frequency is above the allowed range, so the inverter disconnects per grid-protection (anti-islanding) rules. Usually a grid-side event.
F48	Deye	AC under-frequency	Grid frequency is below the allowed range, so the inverter disconnects per grid-protection rules (official manual: 'AC lower frequency - grid frequency out of range'). Usually a grid-side event.
F55	Deye	DC bus voltage too high	The internal DC bus (busbar) voltage is too high (official manual: 'DC busbar voltage is too high - BUS voltage is too high') - typically because battery voltage or PV input voltage is above the allowed range.
F56	Deye	DC bus voltage too low	The internal DC bus (busbar) voltage is too low - most often a flat or very low battery, or insufficient PV. Confirmed in the official manual as 'DC busbar voltage is too low - battery voltage low'.
F58	Deye	BMS communication fault	Communication between the hybrid inverter and the battery BMS has been lost. The official manual flags it as a fault when the 'BMS_Err-Stop' protection is enabled and the BMS link drops (e.g. wrong comms cable, wrong battery protocol, or a loose RJ45).
F63	Deye	ARC fault (AFCI)	The arc-fault detection (AFCI) circuit has detected a possible DC arc on the PV side. The official manual notes this detection is enabled for the US market; many AU units will not raise it.
F64	Deye	Heat-sink high temperature failure	The inverter's heat sink is too hot and it has shut down to protect itself (official manual: 'Heatsink high temperature failure - heatsink temperature is too high') - usually caused by a hot/poorly ventilated install location or blocked airflow.
AC Frequency Out Of Range	Enphase	Grid frequency too high or too low	The microinverter is measuring a grid frequency outside its safe operating band (nominal 50 Hz in Australia) and goes offline as required by grid-protection rules. It must stay off until the grid has been continuously within limits for a set period; if frequency strays again during that window, the timer restarts.
AC Voltage Out Of Range	Enphase	Grid voltage too high or too low	The microinverter is measuring AC (grid) voltage outside the limits set by its grid profile, so it disconnects and stops exporting until the grid settles back within range. In Australia high readings are extremely common on long suburban streets at midday when lots of solar is exporting and pushing local voltage up.
DC Power Too Low	Enphase	Panel producing too little power	Closely related to DC Voltage Too Low — the microinverter is measuring DC power below its operating threshold. Most often this is just low light (dawn, dusk, shade, cloud). If it occurs in full sun, it can point to a shaded, soiled or underperforming panel, or a degraded DC connection.
DC Resistance Low - Power Off	Enphase	Insulation resistance to earth too low	An insulation-resistance (IR) sensor in the microinverter measures the resistance to earth from the positive and negative DC inputs. If it drops below the acceptable threshold (around 7 kΩ on IQ units), the unit stops producing and latches off. On IQ8 units this shows as a solid red status LED (after DC power has been cycled), and the gateway keeps reporting the fault until it is cleared. Common causes are moisture ingress, damaged cabling/connectors, or degraded module insulation.
DC Voltage Too High	Enphase	Too much DC input from the panel	The microinverter reports DC input voltage from the solar module above its rated maximum. On a correctly matched panel/microinverter pairing this is unusual and generally suggests a microinverter malfunction or a module/wiring mismatch.
DC Voltage Too Low	Enphase	Not enough DC input from the panel	The microinverter is seeing DC input voltage from its solar module below the level needed to operate. This is completely normal early morning, late evening, in heavy shade, or on very overcast days. If it appears in good daylight, it can indicate a poor or broken DC connection between the panel and the microinverter, or — on a new system — that a grid profile still needs to be applied at commissioning before the units will produce.
Device Produced No Power	Enphase	No energy generated in the last 24 hours	A microinverter that previously produced has generated no power within the last 24 hours. Causes range across the grid (a profile/voltage/frequency condition keeping it off), the AC side (a tripped breaker or isolator), or a failed unit.
Gateway / Envoy Not Reporting	Enphase	IQ Gateway not sending data to Enphase	The IQ Gateway (Envoy) itself has stopped uploading data to the Enphase cloud, so the whole system appears offline in the app. This is almost always an internet/connectivity problem (router, Wi-Fi, or the gateway's own connection) rather than a solar production fault — your panels may still be generating normally.
GFI Tripped	Enphase	Ground-fault current detected	The microinverter's built-in ground-fault (GFI) sensor has detected leakage current to earth during normal operation and has opened the circuit to protect against a fault. It can be triggered by moisture/weather, but a persistent trip points to damaged module insulation (such as cracked module glass), a damaged connector or cable, or water ingress.
Grid Gone	Enphase	No grid / AC supply detected	The microinverter has disconnected from the grid/mains because it cannot detect a valid supply, so it shuts down. Enphase units are anti-islanding by design and will not produce power without a stable grid present. This appears during a blackout, or when an AC isolator, breaker or RCD on the solar circuit has been switched off.
Microinverter Failed to Report	Enphase	Gateway has lost contact with a microinverter	The IQ Gateway is no longer receiving data from one or more microinverters over the powerline communication (PLC) link, so the panel shows grey (not reporting). It can be caused by powerline-communication interference (e.g. a surge strip, noise source, or the gateway being plugged into a power board rather than a wall outlet), a tripped solar breaker/isolator, an AC wiring issue, or a failed unit — it does not necessarily mean the panel has stopped producing.
Microinverter Not Detected / Not Found	Enphase	New microinverter not discovered during commissioning	During or after installation the IQ Gateway / Enphase Installer App cannot find a microinverter to add it to the system. This is a commissioning-stage condition (the device shows as "not discovered") rather than a logged operational fault, and usually means the unit isn't yet powered, hasn't been given time to be discovered, or its serial wasn't scanned correctly.
Over Temperature / Critical Temperature	Enphase	Microinverter running too hot	An internal temperature measurement inside the microinverter is above its normal range. To protect itself it automatically reduces (derates) its power output, and in extreme cases shuts down, until it cools; full power resumes once the temperature falls to an acceptable level. Note this is an internal reading, not ambient air temperature (IQ8 units run at full power up to about 50 °C ambient and derate above that). It can be driven by very high roof temperatures or restricted airflow behind the panel.
102	Fronius	AC voltage too high	The grid voltage measured at the inverter is above the safe threshold, so it disconnects to protect itself. The single most common Fronius state.
103	Fronius	AC voltage too low	The grid voltage is below the inverter's acceptable range.
105	Fronius	AC frequency too high	The grid frequency is above the acceptable range.
106	Fronius	AC frequency too low	The grid frequency is below the acceptable range.
107	Fronius	No AC grid / outside limits	No grid is available, or several grid parameters are out of range, so the inverter can't synchronise.
108	Fronius	Stand-alone operation detected	The inverter detected an islanding condition (running disconnected from the grid).
112	Fronius	RCMU error	An error in the residual-current monitoring unit (RCMU).
301	Fronius	Overcurrent (AC)	A momentary AC over-current inside the inverter.
302	Fronius	Overcurrent (DC)	A momentary DC over-current inside the inverter.
303	Fronius	DC module over-temperature	The DC power stage is too hot — usually blocked ventilation, high ambient temperature, or units mounted too close.
304	Fronius	AC module over-temperature	The AC power stage is too hot — same causes as 303.
306 · POWER LOW	Fronius	PV output too low	The intermediate-circuit voltage is too low to feed in — usually just low light.
307 · DC LOW	Fronius	DC input voltage too low	The DC input voltage is too low for grid feed-in.
309	Fronius	DC input voltage MPPT 1 too high	The DC voltage on tracker 1 exceeds the inverter's maximum.
311	Fronius	DC string polarity reversed	A DC string is wired with reversed polarity.
313	Fronius	DC input voltage MPPT 2 too high	The DC voltage on tracker 2 exceeds the inverter's maximum.
326 · 327	Fronius	Fan error	A cooling-fan fault (fan 1 or fan 2).
425	Fronius	No communication with power stage	The control can't communicate with the power-stage set.
436	Fronius	Board incompatibility	Functional incompatibility between PC boards (often after a component replacement).
443	Fronius	Intermediate-circuit voltage fault	The intermediate-circuit voltage is too low or asymmetric.
447	Fronius	Insulation fault	An insulation fault in the inverter or PV array.
448	Fronius	Neutral conductor not connected	The neutral wire is not connected.
450	Fronius	Guard cannot be found	The safety guard module was not detected.
452	Fronius	Processor communication error	A communication error between the inverter's processors.
463	Fronius	Reversed AC polarity	The AC connector is inserted incorrectly or the phase is reversed.
502	Fronius	Insulation error on the PV modules	An insulation fault between the array (DC+/DC−) and earth — frequently in damp or rainy weather.
509	Fronius	No feed-in for 24 hours	The inverter hasn't fed energy into the grid in the past 24 hours.
516	Fronius	No communication with storage unit	The inverter can't communicate with the connected battery/storage unit.
517	Fronius	Power derating by temperature	The inverter is reducing output because it's too hot.
567	Fronius	Volt-Watt power reduction (GVDPR)	Grid-Voltage-Dependent Power Reduction (Volt-Watt mode) is active — the inverter is curtailing output because the grid voltage is high.
1	GoodWe	SPI failure	An internal communication (SPI bus) failure inside the inverter.
2	GoodWe	EEPROM R/W failure	A read/write failure on the inverter's memory chip.
3 · Fac Failure	GoodWe	Grid frequency fault	The grid frequency is outside the inverter's permissible range.
7 · 25	GoodWe	Relay check failure	The inverter's grid relay failed its self-check.
12	GoodWe	LCD communication failure	A communication error between the LCD/display and the master DSP.
13	GoodWe	DC injection high	The DC component of the AC output current exceeds the inverter's limit.
14 · Isolation Fail	GoodWe	Isolation failure	Insulation resistance between the PV array and ground is too low — most common in rain or high humidity.
15 · Vac Failure	GoodWe	Grid voltage fault	The grid voltage is outside the acceptable range for the inverter.
16	GoodWe	External fan failure	The external cooling fan has faulted.
17 · PV Over Voltage	GoodWe	PV over-voltage	The PV array voltage exceeds the inverter's maximum input.
19 · Over Temperature	GoodWe	Over temperature	The inverter's operating temperature has exceeded its safe limit.
20	GoodWe	Internal fan fault	An internal cooling-fan fault (IFAN).
21	GoodWe	DC bus high	The internal DC bus voltage is too high.
22 · Ground I Fail	GoodWe	Ground (residual) current failure	Residual-current (earth-leakage) protection has tripped — current is leaking to ground.
23 · Utility Loss	GoodWe	Utility (grid) loss	Loss of connection between the inverter and the utility grid — an outage or a disconnection.
24 · 31	GoodWe	AC HCT (current sensor) failure	The AC current sensor (HCT) has failed.
26 · 32	GoodWe	GFCI failure	A failure in the leakage-current (GFCI) detection circuit.
30	GoodWe	Reference 1.5 V failure	The internal 1.5 V reference voltage is out of range.
Device Failure	GoodWe	Internal device failure	A general internal device failure (shown for faults outside the listed codes).
PE Loss	GoodWe	Protective earth (PE) loss	A missing or faulty protective-earth connection — possibly loose wiring, corrosion, or grounding-system damage.
100	Growatt	Reference voltage fault	An internal 2.5 V reference-voltage fault — a hardware-level problem on the control board.
101	Growatt	Communication fault	Loss of data between the main (DSP) and slave processors inside the inverter.
102	Growatt	Master/slave data mismatch	The data received by the master and slave processors disagree, often triggered by an unstable grid.
116	Growatt	EEPROM fault	A fault in the inverter's internal (EEPROM) memory.
117	Growatt	Relay fault	The internal grid relay is stuck (contacts welded) or its coil has failed.
118	Growatt	Initialisation / model fault	The inverter failed to initialise correctly (model/config fault).
119	Growatt	GFCI device damage	The internal residual-current (GFCI/RCD) sensor is damaged.
120	Growatt	HCT (current sensor) fault	The Hall-effect current sensor is reading inaccurately or has failed.
121	Growatt	Slave processor communication loss	The master processor cannot receive data from the slave processor.
122	Growatt	Bus voltage fault	The internal DC bus voltage is out of its normal range.
201 · Residual I High	Growatt	Residual (leakage) current high	Earth-leakage current from the PV system has exceeded the safety threshold.
202 · PV Voltage High	Growatt	PV input voltage too high	The PV string voltage exceeds the inverter's maximum input rating.
203 · PV Isolation Low	Growatt	PV isolation (insulation) low	Low insulation resistance between the array and ground — most common in rain or high humidity.
205 · PV Boost Broken	Growatt	PV boost circuit broken	The DC-DC boost converter circuit is damaged.
300 · AC V Outrange	Growatt	Grid voltage out of range	The grid voltage is too high (often above ~255–270 V) or too low for the inverter to stay connected.
302 · No AC Connection	Growatt	No AC connection	No grid is connected — a grid outage, an open main switch, or a missing phase / open neutral.
303 · PE Abnormal	Growatt	PE (earth) abnormal	A grounding fault — the voltage between neutral and protective earth (PE) is too high.
304 · AC F Outrange	Growatt	Grid frequency out of range	The grid frequency is outside the permitted range (deviating from 50/60 Hz).
408 · Over Temperature	Growatt	Over temperature	The inverter's internal temperature has exceeded its limit.
Auto Test Failed	Growatt	Auto-test failed	The inverter's self-test (a grid-protection test required in some regions) did not pass.
Output High DCI	Growatt	Output DC injection high	The DC component of the inverter's AC output current is too high.
2001	Huawei	High string input voltage	Open-circuit voltage exceeds the maximum input voltage.
2002	Huawei	DC arc fault	The PV string power cable arcs or is in poor contact. Cause ID 1 = PV1, Cause ID 2 = PV2.
2003	Huawei	DC arc fault	The PV string power cable arcs or is in poor contact. Cause ID 1 = PV1, Cause ID 2 = PV2.
2011	Huawei	String reversed	The PV string is reverse-connected. Cause ID 1 = PV1, Cause ID 2 = PV2.
2012	Huawei	String current back-feed	Only a few PV modules are connected in series in the string, so its end voltage is lower than the other strings. Cause ID 1 = PV1, Cause ID 2 = PV2.
2021	Huawei	AFCI check failure	The AFCI self-check fails — either the AFCI check circuit is abnormal, or the AFCI circuit is faulty.
2031	Huawei	Phase wire short-circuit to PE	The impedance of the output phase wire is low, or it is short-circuited to PE.
2032	Huawei	Grid failure	The grid is experiencing an outage, the AC circuit is disconnected, or the AC switch is off.
2033	Huawei	Grid under-voltage	The grid voltage is below the lower threshold, or the under-voltage duration exceeds the value specified by LVRT.
2034	Huawei	Grid over-voltage	The grid voltage is above the upper threshold, or the over-voltage duration exceeds the value specified by HVRT.
2035	Huawei	Unbalanced grid voltage	The difference between grid phase voltages exceeds the upper threshold.
2036	Huawei	Grid over-frequency	Grid exception: the actual grid frequency is higher than the local grid standard allows.
2037	Huawei	Grid under-frequency	Grid exception: the actual grid frequency is lower than the local grid standard requires.
2038	Huawei	Unstable grid frequency	Grid exception: the rate of change of grid frequency does not comply with the local grid standard.
2039	Huawei	Output over-current	The grid voltage drops dramatically or the grid is short-circuited, so the inverter's transient output current exceeds the upper threshold and protection is triggered.
2040	Huawei	Output DC component over-high	The DC component of the inverter output current exceeds the specified upper threshold.
2051	Huawei	Abnormal residual current	The insulation impedance of the input side to PE decreases while the inverter is operating.
2061	Huawei	Abnormal grounding	The N cable or ground cable is not connected. When a PV array is grounded, the inverter output is not connected to an isolation transformer.
2062	Huawei	Low insulation resistance	The PV array is short-circuited to PE, or the array's environment is damp and insulation between the array and ground is poor.
2063	Huawei	Over-temperature	The inverter is installed in a poorly ventilated location, or the ambient temperature is too high.
2064	Huawei	Device fault	An unrecoverable fault has occurred on a circuit inside the inverter.
2065	Huawei	Upgrade failed / software version mismatch	The upgrade did not complete normally.
2066	Huawei	License expired	The privilege certificate has entered its grace period; the privileged feature will become invalid soon.
2067	Huawei	Faulty power collector	Communication with the power meter is interrupted.
2068	Huawei	Battery abnormal	The battery is faulty or disconnected, or the battery circuit breaker is off while the battery is running.
2070	Huawei	Active islanding	During a grid AC outage, the inverter proactively detects islanding.
2072	Huawei	Transient AC over-voltage	The inverter detects that the phase voltage exceeds the transient AC over-voltage protection threshold.
2077	Huawei	Off-grid output overload	The off-grid output is overloaded or short-circuited.
2080	Huawei	Abnormal PV module configuration	PV module configuration does not meet requirements, or the module output is reverse-connected or short-circuited. Cause IDs — 2: too many optimisers in a single string; 3: too few optimisers in a string, or abnormal sunlight; 5: abnormal optimiser output voltage; 6: abnormal string or parallel connection; 7: string configuration changed.
2081	Huawei	Optimiser fault	The optimiser is offline or faulty.
2082	Huawei	Grid-tied / off-grid controller abnormal	The inverter fails to communicate with the Smart Backup Box, or an unrecoverable fault has occurred inside the Smart Backup Box.
2085	Huawei	Built-in PID operation abnormal	The output resistance of the PV arrays to ground is low, or the system insulation resistance is low.
2090	Huawei	Abnormal active power scheduling instruction	The DI input is abnormal, or inconsistent with the configuration.
2091	Huawei	Abnormal reactive power scheduling instruction	The DI input is abnormal, or inconsistent with the configuration.
61440	Huawei	Monitoring unit faulty	The flash memory is insufficient, or it has bad sectors.
1002	Sigenergy	Low insulation resistance (ISO fault)	The inverter has measured low insulation resistance on the PV (DC) side — meaning the system is detecting a possible leakage path to earth. Common triggers are moisture ingress in a connector or cable, a damaged DC cable, or a string partially shorting to the protective earth (PE). It often appears in the early morning when humidity is highest and may self-clear as things dry out.
1003	Sigenergy	Inverter over-temperature	The inverter has exceeded its safe internal operating temperature and has throttled or shut down to protect itself. Usual causes are high ambient temperature, the unit sitting in direct sun, or restricted airflow/poor ventilation around the tower.
1006	Sigenergy	String input overvoltage (PV)	The DC voltage from a PV string (the sub-ID identifies which string — e.g. ID1 = String 1) is above the inverter's maximum allowed input voltage. This almost always means too many panels were wired in series for that string, and the problem shows up worst on cold, bright mornings when panel voltage peaks.
1009	Sigenergy	AFCI fault (DC arc detected)	The arc-fault circuit interrupter has detected what looks like an electrical arc on a PV string (the sub-ID flags which string). This is a genuine fire-safety feature — arcs are usually caused by a damaged DC cable, a loose or corroded connector, or a poor contact at a string terminal.
1010	Sigenergy	Grid power outage / grid power failure lock	The inverter has detected that the grid has gone away — either an actual blackout or the AC isolator/main switch being turned off (ID1). A persistent or repeated loss can put the system into a grid-failure lock state (ID2). With backup configured, the system transfers to battery/backup; otherwise it stops exporting and waits.
1011	Sigenergy	Grid overvoltage (Level I / II / III)	The grid voltage at your connection point has risen above the allowed protection threshold, so the inverter disconnects to protect itself and comply with grid rules. Level I is mildest, Level III most severe. This is one of the most common alarms in Australia, especially around midday in areas with lots of rooftop solar pushing voltage up.
1012	Sigenergy	Grid undervoltage (Level I / II / III)	The grid voltage has dropped below the protection threshold, so the inverter disconnects until it recovers. It usually reflects a weak or sagging grid supply rather than an inverter fault, and is more common on long rural feeders or during high-demand periods.
1013	Sigenergy	Grid overfrequency (Level I / II / III)	The grid frequency has risen above the allowed threshold and the inverter has disconnected per grid protection rules. This is a grid-side condition, not an internal fault, and usually clears within seconds.
1014	Sigenergy	Grid underfrequency (Level I / II / III)	The grid frequency has fallen below the allowed threshold and the inverter has disconnected to comply with grid protection requirements. Like overfrequency, it is a grid-side event that normally clears within seconds.
1017	Sigenergy	Leak current out of limit	The inverter has measured residual/leakage current above its safety threshold. It is often transient — caused by damp conditions or a momentary disturbance — and the system typically recovers once the environment settles.
1018	Sigenergy	Communication fault (4G / CAN / meter / gateway)	A communication link inside the system has dropped — for example the 4G/monitoring module (ID1), the battery CAN bus (ID2), the energy meter (ID3), or the gateway (ID4). The sub-ID identifies which link. Monitoring or energy-management features may stop working while it is active even if power flow continues.
1022	Sigenergy	EPO / emergency stop activated	The emergency power-off (EPO) input has been triggered — typically because someone pressed the emergency-stop button (or, on some installs, a shutdown command in the mySigen app). The system stays shut down for safety until the EPO is released.
1023	Sigenergy	Neutral disconnected / abnormal AC wiring	The inverter has detected a problem with the AC wiring — most commonly a neutral conductor that is disconnected or has worked loose inside the inverter (ID1), or otherwise abnormal AC wiring (ID2). A poor neutral connection can be a safety hazard.
101 · 102 · 103 · 105	SMA	Grid voltage / impedance too high	The grid voltage or grid impedance at the inverter's connection point is too high, so it disconnects.
202 · 203 · 205	SMA	Grid disconnected / voltage too low	The grid has been disconnected, the AC cable is damaged, or the grid voltage is too low.
301	SMA	10-minute average voltage out of range	The ten-minute average grid voltage is outside the permissible range.
302	SMA	Power reduced — high AC voltage	The inverter has reduced its output because the grid voltage is high (Volt-Watt response, to support grid stability).
401 · 404	SMA	Islanding / frequency change	A stand-alone (islanded) grid or a very large change in grid frequency was detected.
501	SMA	Grid frequency out of range	The power frequency is outside the permissible range.
601	SMA	Excess DC in grid current	The inverter detected an excessively high proportion of direct current in the grid current.
901	SMA	Grounding (PE) connection missing	The protective-earth (grounding) conductor is not correctly connected.
1001	SMA	Line and neutral swapped	The L (active) and N (neutral) connections are swapped.
1302	SMA	Waiting for grid voltage	L or N is not connected (or an AC conductor is damaged) — often simply a mains outage.
1501	SMA	Reconnection fault (country dataset)	A changed country dataset or parameter value doesn't match local requirements.
3301 · 3302 · 3303	SMA	Unstable operation (low DC)	There isn't enough power at the DC input for stable operation.
3401 · 3402 · 3407	SMA	DC over-voltage	Over-voltage at the DC input — this can destroy the inverter.
3501	SMA	Insulation failure (ground fault)	A ground fault / low insulation resistance detected on the DC (PV) side — safety-critical, and common in wet weather.
3701	SMA	Residual current too high	The inverter detected an excessive residual (earth-leakage) current — an electric-shock hazard.
3801 · 3802 · 3805	SMA	DC over-current	Over-current at the DC input; the inverter briefly interrupts feed-in.
3901 · 3902	SMA	Waiting for DC start conditions	The conditions for feeding into the grid aren't yet met — typically insufficient irradiation.
6501 · 6502 · 6509	SMA	Over-temperature	The inverter has switched off (or derated) due to excessive temperature.
6512	SMA	Minimum operating temperature not reached	It's too cold — the inverter only resumes feed-in once the temperature reaches at least −25 °C.
7500 · 7501	SMA	Fan fault	A cooling fan is not functioning properly.
7701 · 7702 · 7703	SMA	Grid relay defect	The grid disconnection relay is defective or failed its test.
8003	SMA	Power reduced — temperature	The inverter has reduced output for more than ten minutes because of excessive temperature.
9002	SMA	Grid Guard code invalid	The SMA Grid Guard code entered is incorrect, so the protected operating parameters stay locked.
9003	SMA	Grid parameters locked	Changes to the grid parameters are now blocked (they require the Grid Guard code).
9007	SMA	Self-test aborted	The inverter's self-test was terminated.
AC5M Volt Fault / AC10M Volt Fault	SolaX	Sustained grid voltage out of range (5 / 10 minute average)	The grid voltage averaged over a 5-minute (AC5M) or 10-minute (AC10M) window has exceeded the allowable limit — a longer-term over/under-voltage protection separate from the instantaneous trip.
Bus Volt Fault	SolaX	Internal DC bus voltage out of range	The internal DC bus voltage inside the inverter is outside its normal operating range. Can be a transient event tied to PV input fluctuations, or an internal hardware issue.
C1 Bat OVP	SolaX	Battery over-voltage	The battery voltage has risen above the charger's safe limit, so charging stopped to protect the battery and inverter.
C1 Bus OVP / C1 Boost OVP	SolaX	Charger bus / boost over-voltage	An internal voltage rail in the battery charger (DC bus or boost stage) has exceeded its limit and the charger has stopped to protect itself.
C1 Charger OCP / C1 Boost OCP	SolaX	Charger / boost overcurrent	An overcurrent was detected in the battery charger or its boost stage, tripping protection.
C1 Temp High / C1 Temp Low	SolaX	Battery charger over / under temperature	The internal battery charger module is too hot (blocked airflow, high charge current, hot environment) or too cold to operate safely.
CAN1 Fault / C1 CAN Fault	SolaX	Battery / charger CAN communication fault	The inverter has lost CAN-bus communication with the battery (BMS) or internal charger module. On a hybrid system this typically means the battery has dropped offline — common causes include a loose CAN cable, the wrong battery type selected in inverter settings, or a missing 120-ohm termination resistor.
CT / Meter Fault	SolaX	CT clamp or smart meter not detected	The inverter cannot communicate properly with the current transformer (CT) clamp or smart meter used to measure import/export (SolaX: 'the CT or the meter is not connected well'). This affects export limiting and energy monitoring rather than basic generation.
DCI / DCI OCP / RC Fault	SolaX	DC injection (DCI) fault	The inverter detected excessive DC current being injected into the AC grid (or a fault in the DCI sensing). Limiting DC injection is a grid-compliance safety requirement.
DM9000 Fault	SolaX	Network DSP fault	The internal networking/DSP component (DM9000) has faulted, typically affecting communication/monitoring functions.
EPS OCP Fault	SolaX	Overcurrent in EPS (backup) mode	An overcurrent was detected on the backup (EPS) output — for example from a large inrush/surge or a non-linear load when running off battery during an outage.
Fan Fault / Fan Speed Fault	SolaX	Cooling fan fault or abnormal fan speed	A cooling fan (Fan1/Fan2) is not running or is running outside its normal speed range. Often caused by dust, debris or insects blocking the fan, or a worn fan.
Grid Freq Fault	SolaX	Grid frequency out of range	The grid frequency has drifted outside the permitted band (nominal 50 Hz in Australia), so the inverter has disconnected for safety. This is almost always a network/supply condition rather than an inverter fault. (Some SolaX manuals print the description for this fault as 'Grid Voltage out of range' — a documentation typo; the fault itself is frequency-related.)
Grid Lost Fault	SolaX	Grid connection lost	The inverter can no longer detect a stable grid supply, so it has safely shut down. This is anti-islanding protection required under AS/NZS 4777.2 — it stops your system back-feeding the network during a blackout, which could be lethal to line workers. Most often caused by a genuine grid outage, a tripped solar supply breaker, or an AC isolator switched off.
Grid Volt Fault	SolaX	Grid voltage out of range	The mains voltage at your property is outside the allowable window the inverter is permitted to operate within. In Australia a common cause is high voltage (over ~253 V) on sunny afternoons when many local solar systems export at once, forcing inverters to trip. This is correct, code-mandated behaviour, not a defect.
Inv EEPROM / Mgr EEPROM / C1 EEPROM Fault	SolaX	Internal memory (EEPROM) fault	An internal memory chip (inverter, manager or charger EEPROM) has reported a read/write error. Can occasionally be transient but often indicates a hardware fault.
Inv OCP Fault	SolaX	Inverter overcurrent protection	The inverter detected an output overcurrent and tripped to protect itself.
Isolation Fault	SolaX	DC insulation resistance too low	The inverter has measured low insulation resistance between the DC (PV/battery) circuit and earth. This is a safety-critical fault that usually points to moisture ingress, a damaged cable, or a degraded connector/panel — there may be a current leakage path to ground.
Over Temperature Fault	SolaX	Inverter over temperature (Temp Over Fault)	The inverter has exceeded its safe internal operating temperature and has derated or shut down to protect itself. Common in hot weather, poor ventilation, or full-sun wall mounting.
Overload Fault	SolaX	EPS / backup output overloaded	While running on battery backup (EPS mode during a grid outage), the connected load drew more power than the inverter can supply, so it shut the backup output down to protect itself.
PLL Lost Fault	SolaX	Grid synchronisation lost	The inverter could not lock onto (synchronise with) the grid's voltage/frequency waveform — SolaX describes this internally as 'the grid is not good'. Usually a symptom of an unstable or poor-quality grid supply rather than a hardware fault.
PV Config Fault	SolaX	PV input configuration error	The PV connection/configuration setting (SolaX: 'PV Connection Setting Fault') does not match how the strings are actually wired — for example parallel vs independent MPPT input settings.
PV Volt Fault	SolaX	PV input voltage out of range	The DC voltage coming from the solar array is outside the inverter's allowable input window. This can be caused by string-design issues (for example too many panels in a string, which pushes voltage high in cold conditions) or an abnormal string condition.
RCD Fault	SolaX	Residual current (earth leakage) fault	The inverter's internal residual-current monitoring detected leakage current to earth above the safe threshold. Like an isolation fault, this is a safety protection that can indicate a wiring or insulation problem.
Relay Fault	SolaX	Grid relay fault	A self-test of the internal grid-connection relay has failed. The relay is a safety device that disconnects the inverter from the grid, so the unit will not operate until it passes. On X3 (three-phase) hybrids it can also be triggered by a poorly connected neutral or three-phase imbalance.
RTC Fault	SolaX	Real-time clock fault	The inverter's internal real-time clock (date/time) has faulted. Mainly affects time-stamping, scheduling and time-of-use battery functions rather than basic generation.
Sample Fault	SolaX	Detection/sampling circuit fault	An internal measurement (sampling) circuit has returned readings outside expected bounds (SolaX: 'the detection circuit fault'), so the inverter cannot trust its own sensing and has stopped.
SPI / SCI Fault	SolaX	Internal communication fault (master/slave DSP)	An internal communication link between the inverter's processors (SPI between master/slave DSP, or SCI) has dropped. Often a transient glitch that recovers by itself, typically within a few minutes.
SW OCP Fault	SolaX	Software-detected overcurrent	The control software detected an overcurrent condition and shut down as a protective measure.
TZ Protect Fault	SolaX	Hardware overcurrent protection tripped	A fast hardware overcurrent protection (Tripzone) has activated. Sometimes a transient event, sometimes an internal fault.
12power-FAULT	Solis	12 V power supply fault	The internal 12 V power supply has faulted.
AFCI self-test	Solis	AFCI module self-detect fault	The AFCI (arc-fault) module failed its self-detection.
Arcing	Solis	Arc detected in DC circuit	An arc was detected in the DC circuit.
DC-INTF / OV-DCA-I	Solis	DC input over-current	The DC input current is above the allowed limit.
DCinj-FAULT	Solis	High DC injection current	The DC injection into the AC output is too high.
DSP-B-FAULT	Solis	Main–slave DSP comms failure	Communication failed between the main and slave DSP.
G-IMP	Solis	High grid impedance	The measured grid impedance is high.
GRID-INTF01/02	Solis	Grid interference	Grid interference is affecting the inverter.
IG-AD	Solis	Grid current sampling fail	The grid current sampling circuit failed.
IGBT-OV-I	Solis	Over IGBT current	The IGBT current is above the allowed limit.
IGFOL-F	Solis	Grid current tracking fail	The inverter failed to track the grid current.
ILeak-PRO01–04	Solis	Leakage current protection	The leakage (residual) current exceeds the protection limit.
INI-FAULT	Solis	Initialisation system fault	A system fault occurred during initialisation.
Init loop	Solis	Stuck on “initialising”	The inverter cannot start up — the LCD shows “initialising” continuously.
LCD blank	Solis	No power on the LCD	The inverter shows no power on the LCD.
NO-GRID	Solis	No grid voltage	No grid voltage is detected.
OV-BUS	Solis	Over DC bus voltage	The internal DC bus voltage is too high.
OV-DC01–04	Solis	Over DC voltage	The DC input voltage is above the allowed limit.
OV-G-F01/02	Solis	Over grid frequency	The grid frequency is above the allowed limit.
OV-G-I	Solis	Over grid current	The grid current is above the allowed limit.
OV-G-V01–04	Solis	Over grid voltage	The grid voltage is above the allowed limit.
OV-TEM	Solis	Over temperature	The inverter is over temperature.
PV ISO-PRO01/02	Solis	PV isolation protection	Low insulation resistance between the PV array and ground.
RelayChk-FAIL	Solis	Relay check fail	The relay self-check failed.
Reverse-DC	Solis	Reverse DC polarity	The DC connection polarity is reversed.
Reverse-GRID	Solis	Wrong AC polarity	The AC connection polarity is incorrect.
Screen off	Solis	Screen off with DC applied	The screen is off although DC is applied — the inverter may be internally damaged.
UN-BUS01/02	Solis	Under DC bus voltage	The internal DC bus voltage is too low.
UN-G-F01/02	Solis	Under grid frequency	The grid frequency is below the allowed limit.
UN-G-V01/02	Solis	Under grid voltage	The grid voltage is below the allowed limit.
001 (SH)	Sungrow	Grid over-voltage	SH hybrid series: grid over-voltage.
002	Sungrow	Grid over-voltage	The grid voltage exceeds the protective value.
002 (SH)	Sungrow	Grid under-voltage	SH hybrid series: grid under-voltage.
003	Sungrow	Transient over-voltage	The grid transient voltage exceeds the inverter's allowable upper limit.
003 (SH)	Sungrow	Grid over-frequency	SH hybrid series: grid over-frequency.
004	Sungrow	Grid under-voltage	The grid voltage is below the protective value.
004 (SH)	Sungrow	Grid under-frequency	SH hybrid series: grid under-frequency.
005	Sungrow	Grid under-voltage (lower threshold)	The grid voltage is below the protective value — lower than the threshold for code 004.
005 (SH)	Sungrow	No grid	SH hybrid series: no grid detected.
006	Sungrow	AC over-current	The AC output current exceeds the inverter's allowable upper limit.
006 (SH)	Sungrow	Over-high leakage current	SH hybrid series: leakage current too high.
007	Sungrow	Transient AC over-current	A transient AC over-current was detected.
007 (SH)	Sungrow	Grid abnormal	SH hybrid series: grid abnormal.
008	Sungrow	Grid over-frequency	The grid frequency exceeds the protective value.
008 (SH)	Sungrow	Grid voltage unbalance	SH hybrid series: unbalanced grid voltage.
009	Sungrow	Grid under-frequency	The grid frequency is below the protective value.
009 (SH)	Sungrow	PV reverse connection fault	SH hybrid series: PV reverse connection fault.
010	Sungrow	Grid failure (islanding)	A grid failure or islanding condition was detected.
010 (SH)	Sungrow	PV reverse connection alarm	SH hybrid series: PV reverse connection alarm.
011	Sungrow	DC injection over-current	The DC current injected into the AC output exceeds the upper limit.
011 (SH)	Sungrow	PV abnormal alarm	SH hybrid series: PV abnormal alarm.
012	Sungrow	Leakage current over-current	The leakage current exceeds the inverter's allowable upper limit.
012 (SH)	Sungrow	High ambient temperature	SH hybrid series: high ambient temperature.
013	Sungrow	Grid abnormal	The grid voltage or frequency is outside the permissible range, so the inverter cannot connect to the grid.
013 (SH)	Sungrow	Low ambient temperature	SH hybrid series: low ambient temperature.
014	Sungrow	10-minute grid over-voltage	The average grid voltage over 10 minutes exceeds the permissible range.
014 (SH)	Sungrow	Low ISO resistance	SH hybrid series: low insulation (ISO) resistance.
015	Sungrow	Grid over-voltage (higher threshold)	The grid voltage exceeds the protective value — higher than the threshold for code 002.
015 (SH)	Sungrow	Grounding cable fault	SH hybrid series: grounding cable fault.
016	Sungrow	High bus voltage / power	The bus voltage or power is high.
016 (SH)	Sungrow	Arc fault	SH hybrid series: DC arc fault.
017	Sungrow	Grid voltage unbalance	Unbalanced three-phase grid voltage was detected.
017 (SH)	Sungrow	Off-grid load over-power	SH hybrid series: off-grid load over-power.
018 (SH)	Sungrow	Reverse Smart Energy Meter connection	SH hybrid series: Smart Energy Meter connected in reverse.
019	Sungrow	Bus transient over-voltage	The transient bus voltage exceeds the inverter's allowable upper limit.
019 (SH)	Sungrow	Smart Energy Meter communication error	SH hybrid series: Smart Energy Meter communication error.
020	Sungrow	Bus over-voltage	The bus voltage exceeds the inverter's allowable upper limit.
020 (SH)	Sungrow	Grid confrontation	SH hybrid series: grid confrontation.
021	Sungrow	PV1 input over-current	The PV1 input over-current limit was exceeded.
021 (SH)	Sungrow	Parallel communication alarm	SH hybrid series: parallel communication alarm.
022	Sungrow	PV2 input over-current	The PV2 input over-current limit was exceeded.
022 (SH)	Sungrow	BMS communication error	SH hybrid series: battery management system (BMS) communication error.
023 (SH)	Sungrow	Battery polarity reversed	SH hybrid series: battery polarity reversed.
024	Sungrow	Neutral point voltage imbalance	The deviation of the neutral point voltage exceeds the allowable limit.
024 (SH)	Sungrow	Battery alarm	SH hybrid series: battery alarm.
024–025 · 030–034 · 040–042 · 050 · 060 · 076 · 116–117	Sungrow	Device abnormal	An internal device abnormality was detected. (Sungrow groups these codes under a single remedy.)
025 (SH)	Sungrow	Battery abnormal	SH hybrid series: battery abnormal.
028	Sungrow	PV1 reverse connection	PV1 is connected with reversed polarity.
029	Sungrow	PV2 reverse connection	PV2 is connected with reversed polarity.
036	Sungrow	Radiator over-temperature	The radiator (heat sink) temperature is too high.
037	Sungrow	Internal inverter over-temperature	The internal temperature of the inverter is too high.
038	Sungrow	Grid-side relay fault	A relay fault on the grid side was detected.
039	Sungrow	Low PV-to-earth insulation resistance	The insulation resistance of the PV array to earth is low.
041	Sungrow	Leakage current sampling fault	The leakage-current sampling circuit faulted.
043	Sungrow	Inner under-temperature fault	The ambient temperature inside the inverter is too low.
044	Sungrow	Inverter self-test fault	The inverter self-test failed.
045	Sungrow	PV1 boost circuit fault	A fault was detected in the PV1 boost circuit.
046	Sungrow	PV2 boost circuit fault	A fault was detected in the PV2 boost circuit.
047	Sungrow	PV inputs error	The PV inputs order is incorrect.
048	Sungrow	Phase current sampling fault	The phase-current sampling circuit faulted.
051	Sungrow	Load over-power (off-grid mode)	The load power exceeds the limit in off-grid mode.
052	Sungrow	INV under-voltage (off-grid mode)	Inverter under-voltage fault in off-grid mode.
053	Sungrow	Slave DSP grid over-voltage detection	The slave DSP detected that the grid voltage exceeds the inverter's allowable upper limit.
054	Sungrow	Slave DSP grid over-frequency detection	The slave DSP detected that the grid frequency exceeds the inverter's allowable upper limit.
056	Sungrow	Slave DSP leakage current detection	The slave DSP detected that the leakage current exceeds the inverter's allowable upper limit.
059	Sungrow	Master–slave DSP communication alarm	A communication alarm between the master and slave DSP.
061	Sungrow	No inverter model setting	No inverter model has been set.
062	Sungrow	STB5K backup box DI fault	A DI fault of the STB5K backup box.
063	Sungrow	CPLD version undetectable	The version of the CPLD (complex programmable logic device) cannot be detected.
063 (SH)	Sungrow	System alarm	SH hybrid series: system alarm.
064	Sungrow	INV over-voltage (off-grid mode)	Inverter over-voltage fault in off-grid mode.
064 (SH)	Sungrow	System fault	SH hybrid series: system fault.
065	Sungrow	INV under-frequency (off-grid mode)	Inverter under-frequency fault in off-grid mode (default value 47 Hz).
066	Sungrow	INV over-frequency (off-grid mode)	Inverter over-frequency fault in off-grid mode (default value 52 Hz).
067	Sungrow	Temporary grid over-voltage (off-grid mode)	A temporary grid over-voltage in off-grid mode.
070	Sungrow	Defective fans	The fans are defective (−D series only).
071	Sungrow	SPD alarm — AC	An AC surge protection device (SPD) alarm.
072	Sungrow	SPD alarm — DC	A DC surge protection device (SPD) alarm.
075	Sungrow	Parallel inverter RS485 communication error	An RS485 communication error between two inverters in parallel.
078–079	Sungrow	PV string abnormal	A PV string is abnormal.
083	Sungrow	Fan 2 abnormal speed warning	Fan 2 is running at an abnormal speed.
084	Sungrow	Energy Meter reverse cable connection	The Energy Meter cable connection is reversed.
085	Sungrow	Mismatched software version	The software versions do not match.
087	Sungrow	AFCI abnormal	The arc-fault detection (AFCI) module is abnormal.
088	Sungrow	Arc fault	A DC arc fault was detected.
089	Sungrow	AFCI function disabled	The AFCI function is disabled.
100	Sungrow	AC output over-current	The AC output current exceeds the upper limit.
101	Sungrow	Grid over-frequency (higher threshold)	The grid frequency exceeds the protective value — higher than the threshold for code 008.
102	Sungrow	Grid under-frequency (lower threshold)	The grid frequency is below the protective value — lower than the threshold for code 009.
105	Sungrow	SPI auto-test fault (Italy only)	The SPI auto-test failed (Italy only).
106	Sungrow	Abnormal grounding	Neither the PE terminal on the AC connection block nor the second PE terminal on the enclosure is reliably connected.
107	Sungrow	DC injection over-voltage (off-grid mode)	The DC injection of the inverter voltage exceeds the upper limit, in off-grid mode.
113	Sungrow	Temporary bypass over-current	A temporary over-current on the bypass path.
200	Sungrow	Bus hardware over-voltage	The bus voltage exceeds the hardware protective value.
201	Sungrow	Bus voltage too low	The bus voltage is too low.
202	Sungrow	PV hardware over-current	The PV1 or PV2 current exceeds the hardware protective value.
203	Sungrow	PV input voltage exceeds bus voltage	The PV input voltage exceeds the bus voltage.
204	Sungrow	PV1 boost short-circuit fault	A short-circuit fault in the PV1 boost stage.
205	Sungrow	PV2 boost short-circuit fault	A short-circuit fault in the PV2 boost stage.
300	Sungrow	INV over-temperature	Inverter over-temperature fault.
302	Sungrow	PV insulation resistance fault	Low PV insulation resistance.
303	Sungrow	Bypass relay fault	A fault in the bypass relay.
304	Sungrow	Off-grid relay fault	A fault in the off-grid relay.
306	Sungrow	Input and output power mismatch	The input and output power do not match.
308	Sungrow	Slave DSP redundant fault	A redundancy fault on the slave DSP.
309	Sungrow	Phase voltage sampling fault	The phase-voltage sampling circuit faulted.
312	Sungrow	DC injection sampling fault	The DC-injection sampling circuit faulted.
315	Sungrow	PV1 current sampling fault	The PV1 current-sampling channel is anomalous.
316	Sungrow	PV2 current sampling fault	The PV2 current-sampling channel is anomalous.
317	Sungrow	PV1 MPPT current sampling fault	The PV1 MPPT current-sampling circuit faulted.
318	Sungrow	PV2 MPPT current sampling fault	The PV2 MPPT current-sampling circuit faulted.
319	Sungrow	System power supply failure	A failure of the system power supply.
320	Sungrow	Leakage current sensor fault	A fault in the leakage-current sensor.
321	Sungrow	SPI communication failure	Communication faults between the master DSP and the slave DSP.
322	Sungrow	Master DSP communication fault	A communication fault on the master DSP.
401–408	Sungrow	Permanent faults	A permanent fault was recorded. (Sungrow groups these codes under a single remedy.)
409	Sungrow	All temperature sensors fail	All temperature sensors have failed.
501	Sungrow	FRAM1 reading warning	An external-memory read/write warning (FRAM1).
503	Sungrow	Ambient temp sensor open-circuit	Ambient temperature sensor open-circuit warning.
504	Sungrow	Ambient temp sensor short-circuit	Ambient temperature sensor short-circuit warning.
505	Sungrow	Radiator temp sensor open-circuit	Radiator temperature sensor open-circuit warning.
506	Sungrow	Radiator temp sensor short-circuit	Radiator temperature sensor short-circuit warning.
507	Sungrow	DO power settings error	An error in the DO (digital output) power settings.
509	Sungrow	Clock reset fault	The clock has been reset.
510	Sungrow	PV over-voltage fault	The PV voltage exceeds the permissible range.
511	Sungrow	Ambient temp sensor open-circuit	Ambient temperature sensor open-circuit warning.
513	Sungrow	Fan 1 abnormal speed warning	Fan 1 is running at an abnormal speed.
514	Sungrow	Energy Meter communication warning	Abnormal Energy Meter communication (the inverter can still connect to the grid).
532–535	Sungrow	String reverse connection	A PV string is connected with reversed polarity.
548–551	Sungrow	Abnormal PV string current	A PV string current is abnormal.
600	Sungrow	Temporary BDC charging over-current	A temporary over-current during battery (BDC) charging.
601	Sungrow	Temporary BDC discharging over-current	A temporary over-current during battery (BDC) discharging.
602	Sungrow	Clamping capacitor under-voltage	The clamping-capacitor voltage is too low.
603	Sungrow	Temporary clamping capacitor over-voltage	A temporary clamping-capacitor over-voltage.
608	Sungrow	BDC circuit self-check fault	The battery (BDC) circuit self-check failed.
612	Sungrow	BDC over-temperature	The battery (BDC) stage is over temperature.
616	Sungrow	BDC hardware over-current	The battery (BDC) hardware over-current limit was exceeded.
620	Sungrow	BDC current sampling fault	The battery (BDC) current-sampling circuit faulted.
622	Sungrow	Leakage current sampling fault	The leakage-current sampling circuit faulted.
623	Sungrow	Slave DSP communication fault	A slave DSP communication fault.
624	Sungrow	BDC soft-start fault	The battery (BDC) soft-start failed.
703	Sungrow	Battery average under-voltage	The average battery voltage is too low.
707	Sungrow	Battery over-temperature	The battery is over temperature.
708	Sungrow	Battery under-temperature	The battery is under temperature.
711	Sungrow	Instantaneous battery over-voltage	An instantaneous battery over-voltage.
712	Sungrow	Battery average over-voltage	The average battery voltage is too high.
714	Sungrow	Abnormal battery–inverter communication	Abnormal communication between the battery and the hybrid inverter.
715	Sungrow	Battery hardware over-voltage	The battery hardware over-voltage limit was exceeded.
732	Sungrow	Battery over-voltage protection	Battery over-voltage protection has triggered.
733	Sungrow	Battery over-temperature protection	Battery over-temperature protection has triggered.
734	Sungrow	Battery under-temperature protection	Battery under-temperature protection has triggered.
735	Sungrow	Battery charge/discharge over-current protection	Battery charging/discharging over-current protection has triggered.
739	Sungrow	Battery under-voltage protection	Battery under-voltage protection has triggered.
800 · 802 · 804 · 807	Sungrow	BDC internal permanent fault	An internal permanent fault in the battery (BDC) stage. (Sungrow groups these codes under a single remedy.)
832	Sungrow	Battery FET fault	A battery FET fault or electrical switch failure.
834	Sungrow	Battery over-current permanent fault	A battery charging/discharging over-current permanent fault.
836	Sungrow	ID competing failure	An ID-competing failure.
839	Sungrow	Mismatched software version	The software versions do not match.
844	Sungrow	Software self-verifying failure	The software self-verification failed.
864	Sungrow	Battery cell over-voltage	A battery cell over-voltage fault.
866	Sungrow	Battery pre-charge voltage fault	A battery pre-charge voltage fault.
867	Sungrow	Battery under-voltage fault	A battery under-voltage fault.
868	Sungrow	Battery cell voltage imbalance	A battery cell voltage imbalance fault.
870	Sungrow	Battery cable connection fault	A battery cable connection fault.
900 · 901	Sungrow	BDC temperature sensor warning	A battery (BDC) temperature-sensor warning. (Sungrow groups these codes under a single remedy.)
906	Sungrow	Transformer direction recognition error	The transformer direction was recognised incorrectly.
909	Sungrow	Low SOH (State of Health) warning	The battery's State of Health is low.
910	Sungrow	FRAM2 warning	A FRAM2 memory warning.
932	Sungrow	Battery over-voltage warning	A battery over-voltage warning.
933	Sungrow	Battery over-temperature warning	A battery over-temperature warning.
934	Sungrow	Battery under-temperature warning	A battery under-temperature warning.
935	Sungrow	Battery charge/discharge over-current warning	A battery charging/discharging over-current warning.
937	Sungrow	Battery tray voltage imbalance warning	A battery tray voltage imbalance warning.
939	Sungrow	Battery under-voltage warning	A battery under-voltage warning.
964	Sungrow	Battery internal warning	An internal battery warning.
Arc Fault Lockout	Tesla	Arc fault detected — system locked out (PV)	Powerwall 3 (which has a built-in solar inverter) detected arc faults on the DC solar wiring. Tesla states that five arc-fault alerts within 24 hours triggers an arc-fault lockout. Arc faults are usually caused by damaged insulation, loose or poorly seated DC connectors, or frayed wiring — a genuine fire-safety concern.
Breaker Open	Tesla	Powerwall breaker is open / off	The AC circuit breaker that connects your Powerwall to your home is in the open (off) position, so the Powerwall is disconnected and can't charge or store energy. Left like this, the battery can slowly drain its reserve and may eventually need a service visit.
Going Off-Grid / Grid Outage	Tesla	Grid is down — running on backup	Status notification (not a fault): the grid has gone down (or you initiated Go Off-Grid) and your home is now running on Powerwall backup. Tesla sends this so you can manage your energy use during the outage. Note that if your internet is also down during an outage, this notification may not arrive.
Internal Fault — Replacement Required	Tesla	Powerwall disabled by an internal fault	Powerwall has been disabled because of an internal hardware fault, and you may see a flashing red logo LED on the unit with an app alert such as 'Powerwall Disabled' or 'Internal Fault Detected'. Powerwall and its components are not user-serviceable — a persistent internal fault means the unit needs professional support or replacement.
Powerwall Energy Very Low	Tesla	Powerwall energy very low — limited backup remaining	The battery is nearly empty during an outage and may fully discharge if usage isn't cut back. Tesla's wording is along the lines of 'Powerwall energy is very low, and you will have limited backup time remaining.' Once it gets too low it stops providing power to protect the cells.
Powerwall Inactive	Tesla	Powerwall has stopped powering the home (inactive)	Powerwall has entered an inactive state — commonly after running very low on energy during an outage or after repeated overloads — and is no longer supplying your home. Tesla notes that when low, if the remaining energy decreases by more than about 2.5% it becomes inactive and waits for the next hour to try charging again.
Powerwall Low on Energy	Tesla	Powerwall is low on energy	Battery charge is getting low (typically during a grid outage). Backup time is limited and will run out sooner if your usage stays high.
Powerwall Overloaded	Tesla	Powerwall is overloaded — reduce load	During a grid outage your home is drawing more power than the Powerwall can supply at once (for example several high-draw appliances running together), so Powerwall has stopped supplying power to protect itself.
Powerwall Stopped (Discharged)	Tesla	Powerwall too low and stopped powering the home	The battery dropped to its minimum and has stopped supplying power to protect the cells. Tesla documents that if an outage occurs while stored energy is below about 5% you immediately lose backup and Powerwall saves the remaining energy to recharge from solar the next morning; separately, once a Powerwall drops below roughly 10% during an outage it enters standby and stops providing power. Either way this is normal protective behaviour, not a fault.
Rapid Shutdown (RSD) Initiated	Tesla	Rapid shutdown triggered — Powerwall won't power home	The rapid-shutdown safety circuit has been triggered, so Powerwall will not power your home. Tesla's alert typically reads 'Rapid Shutdown Initiated. Check AC breaker and low-voltage rapid shutdown circuit.' This is a safety function tied to the AC breaker and the low-voltage RSD wiring, not a simple consumer button you reset.
Storm Watch Activated	Tesla	Storm Watch is active — charging to full	Status notification (not a fault): Tesla's Storm Watch detected a severe-weather forecast in your area (via national weather services) that could cause an outage, so Powerwall is charging to maximum capacity to give you the most backup protection. It stays in Storm Watch until the weather event passes.