INVT GD350 Series Drive Fault Codes List

Complete reference list of INVT GD350 Series fault codes. Learn to troubleshoot expansion card errors, Encoder (ENC) faults, and Safe Torque Off (STO) status.

INVT GD350 Fault Codes Reference Table

Use the search bar in the table below to quickly find your specific error code.

Goodrive350 Series VFD Faults and Troubleshooting

Fault Code and Meaning	Cause and Remedy
OUt1 [1] Inverter unit phase-U protection	Cause: Acceleration is too fast; IGBT module is damaged; Misacts caused by interference; Drive wires are poorly connected; Shorted to ground. Remedy: Increase acceleration time. Replace the power unit. Check drive wires. Check whether there is strong interference surrounding the peripheral equipment.
OUt2 [2] Inverter unit phase-V protection	Cause: Acceleration is too fast; IGBT module is damaged; Misacts caused by interference; Drive wires are poorly connected; Shorted to ground. Remedy: Increase acceleration time. Replace the power unit. Check drive wires. Check whether there is strong interference surrounding the peripheral equipment.
OUt3 [3] Inverter unit phase-W protection	Cause: Acceleration is too fast; IGBT module is damaged; Misacts caused by interference; Drive wires are poorly connected; Shorted to ground. Remedy: Increase acceleration time. Replace the power unit. Check drive wires. Check whether there is strong interference surrounding the peripheral equipment.
OV1 [7] Over-voltage during acceleration	Cause: Deceleration time is too short; Exception occurred to input voltage; Large energy feedback; Lack of braking units; Dynamic braking is not enabled. Remedy: Check input power. Check whether load deceleration time is too short. Check if the motor starts during rotating. Install dynamic braking units. Check the setup of related function codes.
OV2 [8] Over-voltage during deceleration	Cause: Deceleration time is too short; Exception occurred to input voltage; Large energy feedback; Lack of braking units; Dynamic braking is not enabled. Remedy: Check input power. Check whether load deceleration time is too short. Install dynamic braking units. Check the setup of related function codes.
OV3 [9] Over-voltage during constant speed running	Cause: Exception occurred to input voltage; Large energy feedback; Lack of braking units; Dynamic braking is not enabled. Remedy: Check input power. Install dynamic braking units. Check the setup of related function codes.
OC1 [4] Over-current during acceleration	Cause: Acceleration is too fast; Grid voltage is too low; VFD power is too small; Load transient or exception occurred; To-ground short circuit or output phase loss; Strong external interference; Overcurrent stall protection is not enabled. Remedy: Increase acceleration/deceleration time. Check input power. Select the VFD with larger power. Check if the load is short circuited (to-ground or line-to-line) or if rotation is not smooth. Check the output wiring. Check if there is strong interference. Check the setup of related function codes.
OC2 [5] Over-current during deceleration	Cause: Similar to OC1 (Deceleration too fast; Load transient; Short circuit; etc). Remedy: Increase deceleration time. Check input power and output wiring. Select VFD with larger power. Check for interference.
OC3 [6] Over-current during constant speed running	Cause: Load transient; Grid voltage low; Short circuit; Interference; VFD power too small. Remedy: Check input power. Select VFD with larger power. Check if load is short circuited. Check output wiring and interference.
UV [10] Bus undervoltage fault	Cause: Grid voltage is too low; Overvoltage stall protection is not enabled. Remedy: Check grid input power. Check the setup of related function codes.
OL1 [11] Motor overload	Cause: Grid voltage is too low; Rated motor current is set improperly; Motor stall or load jumps violently. Remedy: Check grid voltage. Reset rated motor current. Check the load and adjust torque boost.
OL2 [12] VFD overload	Cause: Acceleration is too fast; The motor in rotating is restarted; Grid voltage is too low; Load is too large; Power is too small. Remedy: Increase acceleration time. Avoid restart after stop. Check grid voltage. Select the VFD with larger power. Select proper motor.
SPI [13] Phase loss on input side	Cause: Phase loss or violent fluctuation occurred to R, S and T input. Remedy: Check the input power. Check installation wiring.
SPO [14] Phase loss on output side	Cause: Phase loss occurred to U, V, W output (or the three phases of motor is asymmetrical). Remedy: Check the output wiring. Check the motor and cable.
OH1 [15] Overheat of rectifier module	Cause: Air duct is blocked or fan is damaged; Ambient temperature is too high; Long-time overload running. Remedy: Ventilate the air duct or replace the fan. Lower the ambient temperature.
OH2 [16] Overheat of inverter module	Cause: Air duct is blocked or fan is damaged; Ambient temperature is too high; Long-time overload running. Remedy: Ventilate the air duct or replace the fan. Lower the ambient temperature.
EF [17] External fault	Cause: SI external fault input terminal acts. Remedy: Check external device input.
CE [18] Modbus/Modbus TCP communication fault	Cause: Baud rate is set improperly; Communication line fault; Communication address error; Communication suffers from strong interference. Remedy: Set proper baud rate. Check the wiring of communication interfaces. Set proper communication address. Replace or change the wiring to enhance anti-interference capacity.
ItE [19] Current detection fault	Cause: Poor contact of the connector of control board; Hall component is damaged; Exception occurred to amplification circuit. Remedy: Check the connector and re-plug. Replace the hall component. Replace the main control board.
tE [20] Motor autotuning fault	Cause: Motor capacity does not match VFD (diff > 5 classes); Motor parameter set improperly; Autotuning params deviate sharply; Autotuning timeout. Remedy: Change the VFD model, or adopt V/F mode for control. Set proper motor type and nameplate parameters. Empty the motor load and carry out autotuning again. Check motor wiring and parameter setup. Check whether upper limit frequency is larger than 2/3 of the rated frequency.
EEP [21] EEPROM fault	Cause: R/W error occurred to the control parameters; EEPROM is damaged. Remedy: Press STOP/RST to reset. Replace the main control board.
PIDE [22] PID feedback offline fault	Cause: PID feedback offline; PID feedback source disappears. Remedy: Check PID feedback signal wires. Check PID feedback source.
bCE [23] Braking unit fault	Cause: Braking circuit fault or braking tube is damaged; The resistance of external braking resistor is too small. Remedy: Check the braking unit, replace with new braking tubes. Increase braking resistance.
END [24] Running time is up	Cause: The actual running time of the VFD is larger than the set running time. Remedy: Ask help from the supplier. Adjust the set running time.
OL3 [25] Electronic overload fault	Cause: The VFD releases overload pre-alarm based on the set value. Remedy: Check the load and overload pre-alarm threshold.
PCE [26] Keypad communication fault	Cause: Keypad wire poorly contacted or disconnected; Wire too long/strong interference; Circuit fault on keypad or main board. Remedy: Check the keypad wires to confirm whether fault exists. Check the surroundings to rule out interference source. Replace the hardware and ask for maintenance service.
UPE [27] Parameter upload error	Cause: Keypad wire poorly contacted or disconnected; Wire too long/strong interference; Circuit fault on keypad or main board. Remedy: Check the surroundings to rule out interference source. Replace the hardware and ask for maintenance service.
DNE [28] Parameter download error	Cause: Keypad wire poorly contacted or disconnected; Wire too long/strong interference; Data storage error occurred to the keypad. Remedy: Check the surroundings to rule out interference source. Replace the hardware and ask for maintenance service. Re-backup keypad data.
ETH1 [32] To-ground short circuit fault 1	Cause: VFD output is short connected to the ground; Current detection circuit is faulty; Actual motor power setup deviates sharply from the VFD power. Remedy: Check whether motor wiring is proper. Replace the hall component. Replace the main control board. Reset the motor parameters properly.
ETH2 [33] To-ground short circuit fault 1	Cause: VFD output is short connected to ground; Current detection circuit is faulty; Actual motor power setup deviates sharply from the VFD power. Remedy: Check whether motor wiring is proper. Replace the hall component. Replace the main control board. Reset the motor parameters properly.
dEu [34] Speed deviation fault	Cause: Load is too heavy, or stall occurred. Remedy: Check the load to ensure it is proper. Increase the detection time. Check whether control parameters are set properly.
STo [35] Maladjustment fault	Cause: Control parameters of synchronous motor set improperly; Parameter gained from autotuning is inaccurate; The VFD is not connected to motor. Remedy: Check the load to ensure it is proper. Check whether control parameters are set correctly. Increase maladjustment detection time.
LL [36] Electronic underload fault	Cause: The VFD performs underload pre-alarm based on the set value. Remedy: Check the load and overload pre-alarm threshold.
ENC1o [37] Encoder offline fault	Cause: Encoder line sequence is wrong, or signal wires are poorly connected. Remedy: Check the encoder wiring.
ENC1d [38] Encoder reversal fault	Cause: The encoder speed signal is contrary to the motor running direction. Remedy: Reset encoder direction.
ENC1Z [39] Encoder Z pulse offline fault	Cause: Z signal wires are disconnected. Remedy: Check the wiring of Z signal.
OT [59] Motor over-temperature	Cause: Motor over-temperature input terminal is valid; Exception occurred to temperature detection; Long-time overload running. Remedy: Check whether temperature sensor is proper. Check the wiring of motor over-temperature input terminal. Check the motor and perform maintenance on the motor.
STO [40] Safe torque off	Cause: Safe torque off function is enabled by external forces. Remedy: (Status Indication)
STL1 [41] Exception occurred to safe circuit of channel H1	Cause: The wiring of STO is improper; Fault occurred to external switch of STO; Hardware fault occurred to safety circuit of channel H1. Remedy: Check whether terminal wiring of STO is proper and firm enough. Check whether external switch of STO can work properly and restart it. Replace the control board.
STL2 [42] Exception occurred to channel H2 safe circuit	Cause: The wiring of STO is improper; Fault occurred to external switch of STO; Hardware fault occurred to safety circuit of channel H2. Remedy: Check whether terminal wiring of STO is proper and firm enough. Check whether external switch of STO can work properly and restart it. Replace the control board.
STL3 [43] Exception occurred to channel H1 and channel H2	Cause: Hardware fault occurred to STO circuit. Remedy: Replace the control board.
CrCE [44] Safety code FLASH CRC check fault	Cause: Control board is faulty. Remedy: Replace the control board.
E-Err [55] Repetitive expansion card type	Cause: The two inserted expansion cards are of the same type. Remedy: You should not insert two cards with the same type. Check the type of expansion card, and remove one card after power down.
ENCUV [56] Encoder UVW loss fault	Cause: No electric level variation occurred to UVW signal; Encoder is damaged. Remedy: Check the wiring of UVW.
F1-Er [60] Failed to identify the expansion card in card slot 1	Cause: There is data transmission in interfaces of card slot 1, however, it cannot read the card type. Remedy: Confirm whether the expansion card inserted can be supported. Stabilize the expansion card interfaces after power down. Check whether the insertion port is damaged.
C1-Er [63] Communication timeout occurred to expansion card in slot 1	Cause: There is no data transmission in interfaces of card slot 1. Remedy: Confirm whether the expansion card inserted can be supported. Stabilize the expansion card interfaces after power down. Check whether the insertion port is damaged.
E-DP [29] PROFIBUS card communication timeout fault	Cause: There is no data transmission between the communication card and the host controller (or PLC). Remedy: Check whether the communication card wiring is loose or dropped.
E-NET [30] Ethernet card communication timeout fault	Cause: There is no data transmission between the communication card and the host controller. Remedy: Check whether the communication card wiring is loose or dropped.
PoFF System power failure	Cause: The system is powered off or the bus voltage is too low. Remedy: Check the grid conditions.

 

Advanced Diagnostics: Slots & Black Box

The GD350 Series offers industry-leading diagnostic tools that go beyond simple error codes.

• Slot Identification: The drive has three expansion slots. Faults relating to cards often indicate the specific slot (e.g., communication errors or card configuration mismatches). Always verify the dip switches on the optional cards match the parameter settings in Group P16/P17.
• Safe Torque Off (STO): The GD350 comes standard with SIL2/SIL3 STO inputs. If the display shows “STO”, the drive is in a safe state, not a fault state. The motor cannot receive torque until the safety circuit (H1/H2) is closed.
• Black Box Monitoring: The GD350 records detailed waveform data at the moment of a fault. Using the INVT Workshop PC software or the mobile app (via optional Bluetooth keypad), you can visualize the exact voltage and current curves 500ms before and after the trip.

Frequently Asked Questions (FAQ)

Q: What do “ENC1O” or “ENC1D” codes mean?

A: These are Encoder Faults used in Closed-Loop Vector control.
ENC1O: Encoder Open Circuit (Wire break). Check the PG card connection in the expansion slot.
ENC1D: Encoder Direction Error. The motor is spinning physically, but the encoder counts are decreasing (or vice versa). Swap the A and B phase wires on the terminal block.

Q: The drive displays “STO” and will not run. How do I reset it?

A: STO (Safe Torque Off) cannot be “reset” like a standard fault because it indicates the status of the safety inputs.
Action: You must apply +24V to the STO inputs (H1 and H2). Once the safety circuit is closed, the “STO” message will disappear, and the drive will be ready to run.

Q: I installed a Profinet/EtherCAT card, but I get a communication fault. Why?

A: This is often a slot configuration issue.
1. Ensure the card is seated firmly in the correct slot.
2. Check parameter P16.00 or P17.00 to ensure the drive recognizes the card type.
3. If the PLC disconnects, the drive triggers a “Watchdog” fault to stop the process safely.