Hitachi SJ300 Fault Codes & Troubleshooting List 2026 – Troubleshoot your Hitachi SJ300 high-performance inverter with our updated 2026 guide. Learn to interpret E01-E60 trips, view detailed fault logs in parameter d081, and reset the drive.
The Hitachi SJ300 is a high-performance, flagship industrial inverter designed for heavy-duty applications requiring superior torque control and high-speed precision. Although succeeded by newer models, the SJ300 remains a mainstay in 2026 manufacturing due to its exceptional durability. When the drive detects an internal or external error, the 4-digit LED operator flashes a trip code (e.g., E01, E07, E14).
This guide provides the most updated resources for 2026 to help you diagnose these error codes and get your high-torque industrial systems back online quickly.
Hitachi SJ300 Fault Codes Reference Table
Below is the reference for the SJ300 protective functions. Please match the “E” code appearing on your digital operator with the diagnostic table below to identify the root cause of the shutdown.
| Fault Code and Meaning | Cause and Remedy |
|---|---|
| E01 Over current event while at constant speed | Cause: The inverter output was short-circuited, or the motor shaft is locked or has a heavy load. These conditions cause excessive current for the inverter, so the inverter output is turned OFF. The dual-voltage motor is wired incorrectly. Note: The SJ300 will over current trip at nominally 200% of rated current for models up to –550xxx; nominally 180% of rated current for models –750xxx to –1500xxx. Remedy:
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| E02 Over current event during deceleration | Cause: Excessive current detected during deceleration. Similar causes to E01 (short circuit, locked shaft, heavy load). Remedy:
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| E03 Over current event during acceleration | Cause: Excessive current detected during acceleration. Similar causes to E01. Remedy:
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| E04 Over current event during other conditions | Cause: DC braking power (A054) is set too high, or a current transformer error occurred, or a noise source induced the error. Remedy:
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| E05 Overload protection | Cause: When a motor overload is detected by the electronic thermal function, the inverter trips and turns OFF its output. Remedy:
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| E06 Braking resistor overload | Cause: When the regenerative braking resistor exceeds the usage time allowance or usage ratio, the inverter trips and turns OFF its output to the motor. Remedy:
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| E07 Over voltage protection | Cause: When the DC bus voltage exceeds a threshold, due to regenerative energy from the motor. Remedy:
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| E08 EEPROM error | Cause: When the built-in EEPROM memory has problems due to noise or excessive temperature, the inverter trips and turns OFF its output to the motor. Remedy:
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| E09 Under-voltage error | Cause: A decrease of internal DC bus voltage below a threshold results in a control circuit fault. This condition can also generate excessive motor heat or cause low torque. The inverter trips and turns OFF its output. Remedy:
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| E10 CT (current transformer) error | Cause: If a strong source of electrical interference is close to the inverter or a fault occurs in a built-in CT (current transformer), the inverter trips and turns its output OFF. Remedy:
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| E11 CPU error | Cause: A malfunction in the built-in CPU has occurred, so the inverter trips and turns OFF its output to the motor. Remedy:
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| E12 External trip | Cause: A signal on an intelligent input terminal configured as EXT has occurred. The inverter trips and turns OFF the output to the motor. Remedy:
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| E13 USP (Unattended Start Protection) | Cause: When the Unattended Start Protection (USP) is enabled, an error occurred when power is applied while a Run signal is present. The inverter trips and does not go into Run Mode until the error is cleared. Remedy:
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| E14 Ground fault | Cause: The inverter is protected by the detection of ground faults between the inverter output and the motor during powerup tests. This feature protects the inverter, and does not protect humans. Remedy:
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| E15 Input over-voltage | Cause: When the input voltage is higher than the specified value, it is detected 60 seconds after powerup and the inverter trips and turns OFF its output. Remedy:
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| E16 Instantaneous power failure | Cause: When the input power is removed for more than 15ms, the inverter trips and the output to the motor turns OFF. If the power failure duration exceeds the duration set in parameter B002, it is considered a power failure. Remedy:
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| E21 Inverter thermal trip | Cause: When the inverter internal temperature is above the threshold, the thermal sensor in the inverter module detects the excessive temperature of the power devices and trips, turning the inverter output OFF. Remedy:
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| E23 Gate array error | Cause: An internal inverter error has occurred in communications between the CPU and gate array IC. Remedy:
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| E24 Phase failure detection | Cause: One of three lines of the 3-phase power is missing. Remedy:
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| E30 IGBT error | Cause: When an instantaneous over-current condition occurs on any IGBT (output transistor) device, the inverter alarm trips, then it turns the outputs OFF in order to protect the circuitry. Remedy:
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| E35 Thermistor | Cause: When a thermistor is connected to terminals [TH] and [CM1] and the inverter has sensed the temperature is too high, the inverter trips and turns OFF the output. Remedy:
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| E36 Brake error | Cause: When the inverter releases the brake and cannot detect whether the external brake is ON or OFF within the waiting time (set by parameter B024), the inverter trips and turns OFF the output to the motor. Remedy:
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| —- Under-voltage (brownout) with output shutoff | Cause: Due to low input voltage, the inverter turns its output OFF and tries to restart. If it fails to restart, then the alarm trips to record the under-voltage error event. Remedy:
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| Loop Symbol Automatic restart and phase loss | Cause: The inverter is restarting, due to an over-current, over-voltage, under-voltage, or a phase loss event. Remedy:
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| E6X Expansion card #1 connection error | Cause: An error has occurred in an expansion card or at its connecting terminals. Remedy:
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| E7X Expansion card #2 connection error | Cause: An error has occurred in expansion card #2. Remedy:
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How to Read SJ300 Faults via Monitor Parameters
The Hitachi SJ300 offers deep diagnostic visibility. In 2026, the standard for professional maintenance involves utilizing the drive’s internal monitoring group (d) to see exactly what happened at the moment of failure.
- Trip History (d081 to d086): The SJ300 records the last 6 major trips in its non-volatile memory. Navigate to the Monitor (d) group on the keypad. Parameter d081 displays the most recent fault.
- Detailed Trip Snapshot: While viewing a trip in parameter d081, the display will automatically cycle through the drive status. This includes the output frequency, motor current, and DC bus voltage recorded at the exact millisecond of the trip.
- ProDrive Software: For complex system analysis, you can connect a PC using the RS485 or optional USB interface. This allows for real-time data tracing to identify why intermittent E07 (Overvoltage) or E05 (Overload) trips are occurring.
General Troubleshooting Steps
Before performing a manual reset on your Hitachi SJ300 drive, perform these essential hardware checks:
- Overcurrent (E01 – E04): Indicates an instantaneous spike in current. Check for a short circuit in the motor wiring or a mechanical jam in the machinery. If this occurs during acceleration, check parameter F002 (Acceleration Time).
- Overvoltage (E07): Typically occurs when a high-inertia load decelerates too quickly, forcing energy back into the drive. Increase the Deceleration Time (Parameter F003) or verify the external braking resistor.
- Under-voltage (E09): Check your input power supply. A drop in line voltage or a blown input fuse is a common cause for E09 trips in industrial environments with heavy machinery.
Frequently Asked Questions (FAQ)
Q: How do I reset a fault on the Hitachi SJ300?
A: Once the cause of the trip is resolved, you can reset the drive by:
- Pressing the Stop/Reset key on the digital LED operator.
- Activating the digital input terminal assigned to the RS (Reset) function (Terminal 5 is the default).
- Cycling the main input power (Wait until the display goes completely blank before turning the power back on).
Q: What does the “USP” code mean?
A: USP (Unattended Start Protection) is a safety error, not a hardware fault. It occurs if the “Run” command is active when the drive is powered up. Simply turn the Run command OFF to clear the error.
Q: Why does my drive show “E14” (Ground Fault)?
A: E14 indicates that current is leaking to the earth on the output side. This is often caused by damaged motor insulation or moisture in the cabling. Do not ignore this fault, as it can lead to internal IGBT damage.
Q: Where is the fault history located on the keypad?
A: Navigate to the Monitor Mode (d-group). The history of the last 6 faults is stored in d081 through d086. Each entry provides a log of the electrical conditions present when the fault occurred.