This is the complete fault table for the DEYE GB-SL / GB-SL Pro ESS Energy storage system family — 28 codes shared by 14 model numbers, transcribed from the official manual. On this DEYE device, a fault code means the unit has entered protection and stopped normal operation; a warning leaves it running. The exact indication (LED pattern or display code) is listed per code below.
Last checked against the official manuals on July 11, 2026.
DC input polarity reverse fault.
CauseThe PV (DC) input is connected with reversed polarity.
Recommended fixCheck the PV input polarity and correct the wiring. Seek help from Deye if the system cannot go back to the normal state.
Source:gb-s12k-eu-gb-s15k-eugb-s20k-eu-gb-s15k-eu-gb-s20k-eu-manual.pdf· page 49gb-s5k-eu-gb-s20k-eu-datasheet.pdf· page 44
DC start failure - the internal BUS voltage cannot be built up.
CauseNeither PV nor battery could establish the internal BUS voltage at start-up - insufficient input voltage or a start-up circuit fault.
Recommended fixRestart the inverter. if the fault still exists, contact Deye for help.
Source:gb-s12k-eu-gb-s15k-eugb-s20k-eu-gb-s15k-eu-gb-s20k-eu-manual.pdf· page 49gb-s5k-eu-gb-s20k-eu-datasheet.pdf· page 44
AC side over-current fault (software detection).
CauseThe combined backup-load and common-load power exceeded the inverter's AC output range.
Recommended fixCheck that the backup load power and common load power are within range, restart, and check whether operation is normal. Seek help from Deye if it does not recover.
Source:gb-s12k-eu-gb-s15k-eugb-s20k-eu-gb-s15k-eu-gb-s20k-eu-manual.pdf· page 49gb-s5k-eu-gb-s20k-eu-datasheet.pdf· page 44
Leakage current fault (GFCI).
CauseGround-leakage current exceeded the limit - typically a PV-side cable ground/insulation problem.
Recommended fixCheck the PV-side cable ground connection and restart the system 2-3 times. if the fault still exists, contact Deye for help.
Source:gb-s12k-eu-gb-s15k-eugb-s20k-eu-gb-s15k-eu-gb-s20k-eu-manual.pdf· page 49gb-s5k-eu-gb-s20k-eu-datasheet.pdf· page 44
AC side over-current fault (hardware detection).
CauseThe combined backup-load and common-load power exceeded the inverter's AC output range, tripping the hardware over-current protection.
Recommended fixCheck that the backup load power and common load power are within range, restart, and check whether operation is normal. Seek help from Deye if it does not recover.
Source:gb-s12k-eu-gb-s15k-eugb-s20k-eu-gb-s15k-eu-gb-s20k-eu-manual.pdf· page 49gb-s5k-eu-gb-s20k-eu-datasheet.pdf· page 44
DC side over-current fault (hardware detection).
CauseDC-side current exceeded the hardware limit - a PV module or battery connection problem, or an off-grid start-up with a large load.
Recommended fixCheck the PV module and battery connections; in off-grid mode reduce the connected load. if it remains, switch the DC and AC switches off for one minute and back on; seek help from Deye if it does not recover.
Source:gb-s12k-eu-gb-s15k-eugb-s20k-eu-gb-s15k-eu-gb-s20k-eu-manual.pdf· page 49gb-s5k-eu-gb-s20k-eu-datasheet.pdf· page 44
BUS over-current.
CauseCurrent on the internal high-voltage BUS exceeded the limit - PV input current or battery current settings too high.
Recommended fixCheck the PV input current and battery current settings, and restart the system 2-3 times. if the fault still exists, contact Deye for help.
Source:gb-s12k-eu-gb-s15k-eugb-s20k-eu-gb-s15k-eu-gb-s20k-eu-manual.pdf· page 50gb-s5k-eu-gb-s20k-eu-datasheet.pdf· page 45
Leakage current fault (transient GFCI over-current).
CauseA transient ground-leakage over-current was detected - typically a PV-side cable ground/insulation problem.
Recommended fixCheck the PV-side cable ground connection and restart the system 2-3 times. if the fault still exists, contact Deye for help.
Source:gb-s12k-eu-gb-s15k-eugb-s20k-eu-gb-s15k-eu-gb-s20k-eu-manual.pdf· page 50gb-s5k-eu-gb-s20k-eu-datasheet.pdf· page 45
PV isolation resistance is too low.
CauseThe PV array's insulation resistance to ground is below the limit - damp or damaged PV wiring, or the inverter PE cable is not properly grounded.
Recommended fixCheck that the PV panel connections to the inverter are firm and correct and that the inverter's PE cable is connected to ground. Seek help from Deye if it does not recover.
Source:gb-s12k-eu-gb-s15k-eugb-s20k-eu-gb-s15k-eu-gb-s20k-eu-manual.pdf· page 50gb-s5k-eu-gb-s20k-eu-datasheet.pdf· page 45
The DC busbar is unbalanced.
CauseLarge load-power differences between the three phases, or DC leakage current, unbalanced the internal DC bus.
Recommended fixWait a while and check whether it returns to normal; balance the loads across phases and restart the system 2-3 times. Seek help from Deye if it persists.
Source:gb-s12k-eu-gb-s15k-eugb-s20k-eu-gb-s15k-eu-gb-s20k-eu-manual.pdf· page 50gb-s5k-eu-gb-s20k-eu-datasheet.pdf· page 45
Parallel CAN communication fault.
CauseIn parallel mode, the parallel communication cable connection or inverter communication-address setting is wrong; inverters also report F29 transiently during parallel-system start-up.
Recommended fixCheck the parallel communication cable connections and the communication address setting of each inverter. During start-up it disappears automatically once all inverters are ON; if it still exists, contact Deye for help.
Source:gb-s12k-eu-gb-s15k-eugb-s20k-eu-gb-s15k-eu-gb-s20k-eu-manual.pdf· page 50gb-s5k-eu-gb-s20k-eu-datasheet.pdf· page 45
AC overload fault on the backup output.
CauseThe backup load power exceeded the allowed output power range.
Recommended fixCheck the backup load connection and make sure it is within the allowed power range. if the fault still exists, contact Deye for help.
Source:gb-s12k-eu-gb-s15k-eugb-s20k-eu-gb-s15k-eu-gb-s20k-eu-manual.pdf· page 50gb-s5k-eu-gb-s20k-eu-datasheet.pdf· page 45
Parallel system stop.
CauseOne inverter in the parallel system shut down, so all paralleled hybrid inverters report F41.
Recommended fixCheck the work status of every hybrid inverter in the parallel system and restore the one that shut down. if the fault still exists, contact Deye for help.
Source:gb-s12k-eu-gb-s15k-eugb-s20k-eu-gb-s15k-eu-gb-s20k-eu-manual.pdf· page 50gb-s5k-eu-gb-s20k-eu-datasheet.pdf· page 45
Parallel firmware-version mismatch.
CauseThe firmware versions of the paralleled inverters are not consistent.
Recommended fixCheck whether the inverter firmware versions are consistent and contact Deye to upgrade the software to matching versions.
Source:gb-s12k-eu-gb-s15k-eugb-s20k-eu-gb-s15k-eu-gb-s20k-eu-manual.pdf· page 50gb-s5k-eu-gb-s20k-eu-datasheet.pdf· page 45
Grid frequency out of range (too high).
CauseThe grid frequency is above the range configured in the specification, or the AC cables are loose/incorrectly connected.
Recommended fixCheck that the grid frequency is within the specified range and that the AC cables are firmly and correctly connected. Seek help from Deye if it does not recover.
Source:gb-s12k-eu-gb-s15k-eugb-s20k-eu-gb-s15k-eu-gb-s20k-eu-manual.pdf· page 50gb-s5k-eu-gb-s20k-eu-datasheet.pdf· page 45
Grid frequency out of range (too low).
CauseThe grid frequency is below the range configured in the specification, or the AC cables are loose/incorrectly connected.
Recommended fixCheck that the grid frequency is within the specified range and that the AC cables are firmly and correctly connected. Seek help from Deye if it does not recover.
Source:gb-s12k-eu-gb-s15k-eugb-s20k-eu-gb-s15k-eu-gb-s20k-eu-manual.pdf· page 50gb-s5k-eu-gb-s20k-eu-datasheet.pdf· page 45
BUS voltage is too high.
CauseThe internal BUS voltage exceeded its limit - battery voltage too high or PV input voltage above the allowed range.
Recommended fixCheck whether the battery voltage is too high and that the PV input voltage is within the allowed range. Seek help from Deye if it does not recover.
Source:gb-s12k-eu-gb-s15k-eugb-s20k-eu-gb-s15k-eu-gb-s20k-eu-manual.pdf· page 51gb-s5k-eu-gb-s20k-eu-datasheet.pdf· page 46
BUS voltage is too low.
CauseThe internal BUS voltage is below its limit - typically the battery voltage is too low.
Recommended fixCheck whether the battery voltage is too low; if so, charge the battery from PV or grid. Seek help from Deye if it does not recover.
Source:gb-s12k-eu-gb-s15k-eugb-s20k-eu-gb-s15k-eu-gb-s20k-eu-manual.pdf· page 51gb-s5k-eu-gb-s20k-eu-datasheet.pdf· page 46
Battery 2 terminal voltage is too high.
CauseThe voltage measured at the battery 2 terminals exceeded the limit - battery over-voltage or wrong battery settings.
Recommended fixCheck the battery 2 terminal voltage, restart the inverter twice and restore the factory settings. Seek help from Deye if it does not recover.
Source:gb-s12k-eu-gb-s15k-eugb-s20k-eu-gb-s15k-eu-gb-s20k-eu-manual.pdf· page 51gb-s5k-eu-gb-s20k-eu-datasheet.pdf· page 46
Battery 1 terminal voltage is too high.
CauseThe voltage measured at the battery 1 terminals exceeded the limit - battery over-voltage or wrong battery settings.
Recommended fixCheck the battery 1 terminal voltage, restart the inverter twice and restore the factory settings. Seek help from Deye if it does not recover.
Source:gb-s12k-eu-gb-s15k-eugb-s20k-eu-gb-s15k-eu-gb-s20k-eu-manual.pdf· page 51gb-s5k-eu-gb-s20k-eu-datasheet.pdf· page 46
Battery 1 terminal voltage is too low.
CauseThe voltage measured at the battery 1 terminals is below the limit - the battery is over-discharged or the settings are wrong.
Recommended fixCheck the battery 1 terminal voltage, restart the inverter twice and restore the factory settings. Seek help from Deye if it does not recover.
Source:gb-s12k-eu-gb-s15k-eugb-s20k-eu-gb-s15k-eu-gb-s20k-eu-manual.pdf· page 51gb-s5k-eu-gb-s20k-eu-datasheet.pdf· page 46
Battery 2 terminal voltage is too low.
CauseThe voltage measured at the battery 2 terminals is below the limit - the battery is over-discharged or the settings are wrong.
Recommended fixCheck the battery 2 terminal voltage, restart the inverter twice and restore the factory settings. Seek help from Deye if it does not recover.
Source:gb-s12k-eu-gb-s15k-eugb-s20k-eu-gb-s15k-eu-gb-s20k-eu-manual.pdf· page 51gb-s5k-eu-gb-s20k-eu-datasheet.pdf· page 46
Battery BMS communication lost.
CauseCommunication between the hybrid inverter and the battery BMS disconnected while 'BMS_Err-Stop' is active.
Recommended fixRestore the BMS communication link (cable, pinout, protocol). if you do not want the inverter to stop on BMS loss, disable the 'BMS_Err-Stop' item on the LCD. if the fault still exists, contact Deye for help.
Source:gb-s12k-eu-gb-s15k-eugb-s20k-eu-gb-s15k-eu-gb-s20k-eu-manual.pdf· page 51gb-s5k-eu-gb-s20k-eu-datasheet.pdf· page 46
DRM0 stop (demand response, Australia).
CauseThe DRM0 demand-response signal commanded the inverter to stop, or the DRM function is enabled where it is not in use (the DRM function is for the Australia market only).
Recommended fixCheck whether the DRM function is active and disable it if unused. Seek help from Deye if the inverter does not return to normal after a system restart.
Source:gb-s12k-eu-gb-s15k-eugb-s20k-eu-gb-s15k-eu-gb-s20k-eu-manual.pdf· page 51gb-s5k-eu-gb-s20k-eu-datasheet.pdf· page 46
DC arc fault detected (US market only).
CauseA DC arc was detected in the PV wiring - typically a loose, damaged, or corroded PV module cable connection (ARC detection is for the US market only).
Recommended fixCheck the PV module cable connections, repair the arcing point, and clear the fault. Seek help from Deye if it does not return to normal.
Source:gb-s12k-eu-gb-s15k-eugb-s20k-eu-gb-s15k-eu-gb-s20k-eu-manual.pdf· page 51gb-s5k-eu-gb-s20k-eu-datasheet.pdf· page 46
Heat sink temperature is too high.
CauseThe inverter heat-sink temperature exceeded its limit - working environment temperature too high or insufficient cooling.
Recommended fixCheck whether the working environment temperature is too high; turn the inverter off for 10 minutes and restart. Seek help from Deye if it does not recover.
Source:gb-s12k-eu-gb-s15k-eugb-s20k-eu-gb-s15k-eu-gb-s20k-eu-manual.pdf· page 51gb-s5k-eu-gb-s20k-eu-datasheet.pdf· page 46
Working mode change notice.
CauseReported when the grid type/frequency setting changes, when the battery mode is set to 'No battery', or (on older firmware) when the system work mode changes.
Recommended fixIt generally disappears automatically. if it remains, switch the DC and AC switches off for one minute and back on; seek help from Deye if it will not clear.
Source:gb-s12k-eu-gb-s15k-eugb-s20k-eu-gb-s15k-eu-gb-s20k-eu-manual.pdf· page 49gb-s5k-eu-gb-s20k-eu-datasheet.pdf· page 44
Remote shutdown - the inverter is being remotely controlled.
CauseA remote shutdown command is active; the inverter has been stopped by remote control.
Recommended fixClear or release the remote shutdown command from the remote-control source to resume operation.
Source:gb-s12k-eu-gb-s15k-eugb-s20k-eu-gb-s15k-eu-gb-s20k-eu-manual.pdf· page 50gb-s5k-eu-gb-s20k-eu-datasheet.pdf· page 45
Send us the code on your screen and a DEYE technician will reply with the exact steps for your unit. Support is free for life — a first diagnosis never needs a callout.
Compiled from official DEYE user manuals. Always consult your device manual and a qualified technician before performing repairs.