Huawei Inverter Error Codes
Major and minor alarm codes for Huawei SUN2000 residential and commercial inverters, with plain-English causes and field-tested fixes.
- Manufacturer
- Huawei (SUN2000 series)
- Codes documented
- 35
- Source
- Manufacturer documentation
- Scope
- Reference only
An independent reference compiled by Solar Analytica from publicly available Huawei inverter documentation. It lists the fault and alarm codes a Huawei residential inverter may report, what each one means, and the documented resolution steps. Safety note: anything involving DC isolators, AC switches, wiring, or opening the unit is licensed-electrician work — if in doubt, contact your installer rather than working on a live system.
- 35 Huawei (SUN2000 series) fault and alarm codes, documented in plain English.
- Compiled from manufacturer documentation — independent and not affiliated with Huawei (SUN2000 series).
- Codes involving DC/AC isolators, wiring or opening the unit are licensed-electrician work — when in doubt, call your installer.
35 of 35 codes
- 2001
High string input voltage
Open-circuit voltage exceeds the maximum input voltage.
What to do
Contact your solar installer. Check the number of PV modules connected in series in the PV string, and ensure the string open-circuit voltage is no greater than the maximum operating voltage. Once the PV array is correctly configured, the alarm clears automatically.
- 2002
DC arc fault
The PV string power cable arcs or is in poor contact. Cause ID 1 = PV1, Cause ID 2 = PV2.
What to do
Contact your solar installer. Check whether the string cables arc or are in poor contact.
- 2003
DC arc fault
The PV string power cable arcs or is in poor contact. Cause ID 1 = PV1, Cause ID 2 = PV2.
What to do
Contact your solar installer. Check whether the string cables arc or are in poor contact.
- 2011
String reversed
The PV string is reverse-connected. Cause ID 1 = PV1, Cause ID 2 = PV2.
What to do
Contact your solar installer. Check whether the PV string is reverse-connected to the inverter.
- 2012
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.
What to do
Contact your solar installer, who should check:
- 2021
AFCI check failure
The AFCI self-check fails — either the AFCI check circuit is abnormal, or the AFCI circuit is faulty.
What to do
Turn off the AC output switch and DC input switch, then turn them on again after 5 minutes. If the fault persists, contact your solar installer, dealer, or Huawei technical support.
- 2031
Phase wire short-circuit to PE
The impedance of the output phase wire is low, or it is short-circuited to PE.
What to do
Contact your solar installer. Check the impedance of the output phase wire to PE, locate the position with low impedance, and restore it.
- 2032
Grid failure
The grid is experiencing an outage, the AC circuit is disconnected, or the AC switch is off.
- 2033
Grid under-voltage
The grid voltage is below the lower threshold, or the under-voltage duration exceeds the value specified by LVRT.
- 2034
Grid over-voltage
The grid voltage is above the upper threshold, or the over-voltage duration exceeds the value specified by HVRT.
- 2035
Unbalanced grid voltage
The difference between grid phase voltages exceeds the upper threshold.
- 2036
Grid over-frequency
Grid exception: the actual grid frequency is higher than the local grid standard allows.
- 2037
Grid under-frequency
Grid exception: the actual grid frequency is lower than the local grid standard requires.
- 2038
Unstable grid frequency
Grid exception: the rate of change of grid frequency does not comply with the local grid standard.
- 2039
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
Output DC component over-high
The DC component of the inverter output current exceeds the specified upper threshold.
- 2051
Abnormal residual current
The insulation impedance of the input side to PE decreases while the inverter is operating.
- 2061
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.
What to do
Contact your solar installer. Power off the inverter and check:
- 2062
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.
What to do
Contact your solar installer, who should:
- 2063
Over-temperature
The inverter is installed in a poorly ventilated location, or the ambient temperature is too high.
What to do
Check the ventilation and ambient temperature at the install location. If ventilation is poor or the ambient temperature is above the upper threshold, improve airflow and heat dissipation. If both meet requirements, contact your dealer or Huawei technical support.
- 2064
Device fault
An unrecoverable fault has occurred on a circuit inside the inverter.
What to do
Turn off the AC output switch and DC input switch, then turn them on again after 5 minutes. If the fault persists, contact your dealer or Huawei technical support.
- 2065
Upgrade failed / software version mismatch
The upgrade did not complete normally.
- 2066
License expired
The privilege certificate has entered its grace period; the privileged feature will become invalid soon.
- 2067
Faulty power collector
Communication with the power meter is interrupted.
What to do
Contact your solar installer. Confirm the power meter settings match the actual model, that its communications parameters match the inverter's RS485 settings, that it is powered on, and that the RS485 cable is connected correctly.
- 2068
Battery abnormal
The battery is faulty or disconnected, or the battery circuit breaker is off while the battery is running.
- 2070
Active islanding
During a grid AC outage, the inverter proactively detects islanding.
What to do
Contact your installer. Check that the grid-connection voltage of the inverter is normal.
- 2072
Transient AC over-voltage
The inverter detects that the phase voltage exceeds the transient AC over-voltage protection threshold.
- 2077
Off-grid output overload
The off-grid output is overloaded or short-circuited.
- 2080
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.
What to do
Contact your installer. Check that the total number of PV modules, the number per string, and the number of strings meet requirements, and that module output is not reverse-connected.
- 2081
Optimiser fault
The optimiser is offline or faulty.
What to do
Contact your dealer or Huawei technical support for optimiser replacement.
- 2082
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
Built-in PID operation abnormal
The output resistance of the PV arrays to ground is low, or the system insulation resistance is low.
What to do
Check the impedance between the PV array output and ground; rectify any short circuit or insufficient insulation. Alternatively, turn off the AC output and DC input switches, wait the period stated on the device safety label, then turn the DC input and AC output switches back on. If the alarm persists, contact your dealer or Huawei technical support.
- 2090
Abnormal active power scheduling instruction
The DI input is abnormal, or inconsistent with the configuration.
- 2091
Abnormal reactive power scheduling instruction
The DI input is abnormal, or inconsistent with the configuration.
- 61440
Monitoring unit faulty
The flash memory is insufficient, or it has bad sectors.
What to do
Turn off the AC output switch and then the DC input switch. After 5 minutes, turn on the AC output switch and then the DC input switch. If the fault persists, the board may need replacing — contact your dealer or Huawei technical support.
Frequently asked
- Where do these Huawei fault codes come from?
- We compile them from publicly available Huawei inverter documentation and field references, then rewrite each entry in plain English. Solar Analytica is independent and not affiliated with Huawei.
- Can I clear these faults myself?
- Some clear automatically once conditions return to normal. Anything involving DC isolators, AC switches, wiring or opening the unit is licensed-electrician work — if in doubt, contact your installer rather than working on a live system.
- My exact code isn't listed — why not?
- Firmware and model variants differ, and manufacturers occasionally revise their codes. We document the most common ones; if yours isn't here, check your inverter's manual or ask your installer.
- How current is this reference?
- Last reviewed June 2026. We revise it when the underlying manufacturer documentation changes.
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