Our solar inverter faults guide covers faults on all brands. For GoodWe models and prices see GoodWe inverters, and for a side-by-side with Solis see Solis vs GoodWe.
What GoodWe inverter error codes mean
A GoodWe inverter checks the grid, the solar strings, its own temperature and, on hybrids, the battery. When something is outside its safe range it shows a fault, lights the red indicator and stops or limits output. GoodWe's advice for a red light is simple: read the message on the screen or app, follow your manual's troubleshooting steps, and contact your dealer or GoodWe service if it persists.
Two things to know before using any list:
- Names differ slightly between series. Older and many current models show names like "Utility Loss" or "ISO Failure". An ET-series manual we checked uses "Low Insulation Res." for the same idea.
- Newer models add numbers. The manual for GoodWe's ES Uniq series lists fault codes F01 to F163, plus separate battery fault tables for each battery model. Use your own model's manual for the number.
Reading a GoodWe error
Grid
Voltage and frequency faults
PV
Isolation and over-voltage
Internal
Relay and self-check faults
GoodWe fault codes by type
The tables group common GoodWe faults by type. Meanings are paraphrased from GoodWe's FAQs and manual.
Grid faults, including goodwe utility loss
| Fault name | What it means | Typical cause in Punjab |
|---|---|---|
| Utility Loss | No AC voltage reaching the inverter | Load-shedding, a tripped AC breaker, a voltage protector that has cut out |
| Vac Failure / grid overvoltage or undervoltage | Grid voltage outside the safety-country range | High midday voltage, weak supply, long service cable |
| Fac Failure | Grid frequency outside the range | Unstable grid, or a generator on the grid input |
| Grid 10-min overvoltage | 10-minute average voltage too high | Sustained high voltage at your connection |
| LVRT / HVRT | A low or high voltage lasted longer than the ride-through setting | Grid disturbance |
GoodWe Utility Loss is normal during load-shedding: an on-grid inverter must stop, and a hybrid should keep backup loads running from the battery (see inverter grid fault during load-shedding). If it appears while WAPDA supply is on, GoodWe's own FAQ says to check the grid, the AC breaker and protection switches, and on a new installation the live, neutral and earth wiring. The last part is an installer job.
Vac Failure that repeats on sunny afternoons is usually voltage rise from your own export. GoodWe suggests confirming the voltage and the safety-country setting; changes should only be made by an engineer. See inverter tripping on high grid voltage.
Solar side faults, including goodwe isolation failure
| Fault name | What it means | Owner action |
|---|---|---|
| ISO Failure / Low Insulation Res. | Insulation between the solar wiring and earth too low | Note weather and time; call an engineer if it persists |
| Ground I Failure | Leakage current too high | Call an engineer |
| Ground fault | Earth not connected properly, live and neutral swapped, or a string grounded | Engineer only |
| PV Overvoltage | String voltage above the inverter's DC input range | Engineer only: too many panels in series |
| PV string connected incorrectly | A string wired wrongly | Engineer only |
What owners search for as GoodWe isolation failure is shown as ISO Failure on many models. GoodWe's FAQ describes finding it by reconnecting panels one at a time and checking the faulty panel's earthing and wiring. That is DC work on live circuits and is for a qualified engineer only. Our inverter isolation fault guide explains why damp mornings trigger it.
For PV Overvoltage, GoodWe says to compare the measured string voltage with the DC input range on the inverter's label and reduce panels if it is too high. Winter mornings are the worst case: see PV over voltage error.
Temperature faults
The ET manual lists overtemperature faults caused by poor ventilation, high surrounding temperature or a fan problem. In Punjab summers, shade and airflow fix most of these; see inverter overheating.
Internal faults
| Fault name | What it means |
|---|---|
| Relay Check abnormal | Output relay or control circuit problem, or a short on the output wiring |
| Internal Comm Loss | Internal communication error |
| GFCI HCT check abnormal | Leakage sensor sampling problem |
| Flash fault | Internal memory problem |
| Power Failure | External supply issue or internal fault |
For most internal faults, the manual's advice is to switch off, wait five minutes, restart, and call after-sales service if the fault stays.
Battery faults and the goodwe bms communication error
On GoodWe hybrids, a lithium battery must be connected to the inverter with a BMS communication cable. When that link fails, the inverter cannot read the battery's charge limits and shows a battery or BMS communication fault (exact wording varies by model). Common causes are a loose or wrong cable, a wrong battery selection in settings, or a battery that is not on the inverter's compatibility list. All are installer checks. See battery and inverter communication.
Two GoodWe battery behaviours that look like faults but are not:
- SOC changes after a restart. GoodWe says that after a restart the state of charge is estimated from voltage alone, and becomes accurate again after a full charge and discharge. See battery percentage wrong.
- Battery stops below 100%. Charging stops at the charge voltage set for that battery, which can be below 100% on some batteries.
Meter and export limit
GoodWe's FAQ notes that with a 0 W export limit, a small amount of power (up to about 100 W) may still reach the grid. If export is much higher, see zero export not working.
Quick-check table
| Symptom | Likely cause | Safe owner check | Call an engineer if... |
|---|---|---|---|
| Utility Loss with WAPDA on | Tripped AC breaker or voltage protector | Look at the breaker and protector, without opening the DB | A breaker trips again after one reset |
| Vac Failure on sunny afternoons | Voltage rise | Note times; check voltage in the app | It happens most days |
| ISO Failure on damp mornings | Water at a weak connector or cable | Note weather; view wiring from a safe spot | It persists after drying |
| PV Overvoltage on cold mornings | Too many panels in series | Note the date and time | Always |
| Battery communication fault | Cable, setting or compatibility | Check the battery is switched on | It does not clear after one correct restart |
| Yellow power light blinking | Wi-Fi setup failed | Re-run Wi-Fi setup | The screen also shows a fault |
Safe owner checks, step by step
Safety box. Solar strings carry DC whenever there is daylight, and batteries can deliver very high currents. Never open the inverter or battery, never pull MC4 connectors or battery cables, and never reconnect panels yourself. If you smell burning, see smoke or water inside equipment, or feel a shock from metal, switch off in the order your manual gives, keep away and call a qualified engineer.
- Photograph the screen and the SEMS app alarm with the date and time.
- Note the model and serial number from the side label.
- Check the grid, the AC breaker and any voltage protector.
- Note the pattern: midday, morning damp, rain, load-shedding, a heavy load starting.
- Restart once in the manual's order, with the wait time it gives. See how to restart a solar system safely.
- Keep vents clear and the area around the inverter free.
- If the app is offline but the screen is normal, see solar app offline. A blinking yellow power light means Wi-Fi setup failed; see inverter Wi-Fi setup.
What an engineer will check
- Grid faults: voltage at inverter and meter, AC cable and joints, wiring of live, neutral and earth, and the safety-country setting.
- ISO and Ground I faults: insulation of each string, panel earthing, connectors and cable damage.
- PV Overvoltage: string length against the inverter's maximum at the coldest expected temperature.
- Battery faults: communication cable, port, battery selection, compatibility and BMS log.
- Internal faults: firmware and, if needed, a manufacturer's warranty claim.
How to prevent repeat faults
- Keep the inverter shaded, ventilated and away from afternoon sun.
- Design strings for winter voltage.
- Use matched, properly crimped connectors and protect cables from edges and rodents.
- Wash panels gently, without spraying connectors.
- Use only batteries on the inverter's compatibility list, set correctly.
If Solar Works installed your GoodWe inverter
Our own engineers handle after-sales. WhatsApp 0336 666 4321 with a photo of the screen or app fault and the inverter model. Our 1-year service warranty applies under the applicable project terms; faults in the inverter itself go through the manufacturer's warranty per product. See how after-sales service works.
We can also inspect GoodWe inverters installed by other companies, as a chargeable service, across Punjab.
Frequently asked questions
What does Utility Loss mean on a GoodWe inverter?
It means no grid voltage is reaching the inverter. During load-shedding that is normal. If WAPDA supply is on, check the AC breaker and voltage protector, then call your installer.
How to fix ISO Failure on a GoodWe inverter?
It means insulation between the solar wiring and earth is too low, often at a damp connector or damaged cable. Do not touch the wiring; an engineer must test the strings and repair the weak spot.
What is Ground I Failure on GoodWe?
Leakage current from the solar side is too high. It is a safety fault, so call an engineer rather than restarting repeatedly.
Why does my GoodWe inverter show Vac Failure?
Grid voltage is outside the range set for your country profile. If it happens on sunny afternoons, it is usually voltage rise from export, which an engineer should measure.
Why is my GoodWe battery not communicating with the inverter?
Usually a loose or wrong communication cable, the wrong battery selected in settings, or a battery that is not on the compatibility list. Your installer can check all three.
Why does my GoodWe battery percentage change after restart?
GoodWe says the inverter estimates charge from voltage alone after a restart. It becomes accurate again after a full charge and discharge.
Do you repair GoodWe inverters installed by other companies?
Yes, we can inspect other installers' GoodWe systems across Punjab as a chargeable service. Send the fault photo and model on WhatsApp 0336 666 4321 first.
Sources
- GoodWe, FAQs
- GoodWe Australia, FAQs
- GoodWe, ET Series (15-30 kW) User Manual, troubleshooting section (distributor-hosted copy)
- GoodWe, Residential Smart Inverter Solutions User Manual, ES Uniq 8-12K (contents list)
Help across Punjab
Send the alarm name and a photo of the screen on WhatsApp. We inspect systems in Faisalabad, Lahore and across Punjab, including systems installed by other companies, as a paid visit.
Send us
Photos of the inverter screen or app alarm, your inverter and battery model, and when the problem happens.