Access the complete list of Mitsubishi FR-F700PJ fault codes (E.OC1, E.THT, etc.). Learn to troubleshoot fan & pump drive trips, use FR Configurator2, and view alarm history.

Mitsubishi FR-F700PJ Fault Codes Reference Table (2026)

Below is the complete troubleshooting list for identifying specific drive issues.

 

Mitsubishi FR-F700PJ Fault Codes List

Fault Code and Meaning	Cause and Remedy
HOLD Operation panel lock	Cause: Operation has been attempted during the operation panel lock. Remedy: Press [MODE] for 2s to release the lock.
LOCd Password locked	Cause: Reading/writing of a password-restricted parameter has been attempted. Remedy: Enter the password in Pr. 297 Password lock/unlock to unlock the password function before operating.
Er1 Write disable error	Cause: Parameter setting has been attempted although parameter writing is set to be disabled. Overlapping range has been set for the frequency jump. PU and the inverter cannot make normal communication. Remedy: Check the setting of Pr. 77 Parameter write selection. Check the setting of Pr. 31 to Pr. 36 (frequency jump). Check the connection of PU and the inverter.
Er2 Write error during operation	Cause: Parameter writing has been attempted while a value other than "2" is set in Pr. 77 Parameter write selection and the STF (STR) is ON. Remedy: Set "2" in Pr. 77 Parameter write selection. After stopping the operation, set parameters.
Er3 Calibration error	Cause: Analog input bias and gain calibration values have been set too close. Remedy: Check the settings of calibration parameters C3, C4, C6 and C7 (calibration functions).
Er4 Mode designation error	Cause: Parameter setting has been attempted in the External or NET operation mode when Pr. 77 is not "2". Parameter writing has been attempted when the command source is not at the operation panel. Remedy: After setting the operation mode to the "PU operation mode", set parameters. Set "2" in Pr. 77 Parameter write selection. Remove the parameter unit (FR-PU04/FR-PU07), then set the Pr. 551 PU mode operation command source selection = "9999 (initial setting)." Set Pr. 551 PU mode operation command source selection = "4."
Err. Inverter reset	Cause: The reset signal (RES signal) is ON. (Inverter output is shutoff.) Remedy: Turn OFF the reset command.
OL Stall prevention (overcurrent)	Cause: The overcurrent stall prevention has been activated. Remedy: Increase or decrease the Pr. 0 Torque boost setting by 1% and check the motor status. (V/F control) Set the acceleration/deceleration time longer. Reduce the load. Try the general-purpose magnetic flux vector control. Check the peripheral devices for faults. Adjust the Pr. 13 Starting frequency setting. Change the Pr. 14 Load pattern selection setting. (V/F control) Set the stall prevention operation current in Pr. 22. Check the connection of the IPM motor. (IPM motor control)
oL Stall prevention (overvoltage)	Cause: The overvoltage stall prevention function or the regeneration avoidance function has been activated. Remedy: Set the deceleration time longer.
rb Regenerative brake pre-alarm	Cause: The regenerative brake duty has reached 85% of the Pr. 70 Special regenerative brake duty setting or higher. Remedy: Set the deceleration time longer. Check the Pr. 30 Regenerative function selection and Pr. 70 settings.
TH Electronic thermal relay function pre-alarm	Cause: The cumulative value of the electronic thermal O/L relay has reached 85% of the Pr. 9 setting or higher. Remedy: Reduce the load and frequency of operation. Set an appropriate value in Pr. 9 Electronic thermal O/L relay.
PS PU stop	Cause: [STOP/RESET] on the operation panel has been pressed during the External operation. Remedy: Turn the start signal OFF and release with [PU/EXT].
MT Maintenance signal output	Cause: The cumulative energization time has exceeded the maintenance output timer set value. Remedy: Setting "0" in Pr. 503 Maintenance timer erases the signal.
Uv Undervoltage	Cause: The voltage at the main circuit power has been lowered. Remedy: Investigate the devices on the power supply line such as the power supply itself.
SA Safety Stop (Shorting wire disconnect)	Cause: The shorting wire across the terminals S1 and SC or the terminals S2 and SC is disconnected. Remedy: Short across the terminals S1 and SC and the terminals S2 and SC with shortening wires.
Fn Fan alarm	Cause: The cooling fan is at a standstill although it is required to be operated. The cooling fan speed has decelerated. Remedy: Check for fan failure. Please contact your sales representative.
E.OC1 Overcurrent trip during acceleration	Cause: Overcurrent has occurred during acceleration. Remedy: Set the acceleration time longer. If "E.OC1" always appears at start, disconnect the motor once and restart the inverter. If it still appears, inverter may be faulty. Check the wiring for output short circuit and ground fault. When rated motor frequency is 50Hz, set Pr. 3 Base frequency to 50Hz. Lower the stall prevention operation level. Activate stall prevention and fast-response current limit (Pr. 156).
E.OC2 Overcurrent trip during constant speed	Cause: Overcurrent has occurred during constant speed operation. Remedy: Keep the load stable. Check the wiring to avoid output short circuit or ground fault. Lower the stall prevention operation level. Activate stall prevention and fast-response current limit (Pr. 156). Choose inverter and motor capacities that match.
E.OC3 Overcurrent trip during deceleration or stop	Cause: Overcurrent has occurred during deceleration or at a stop. Remedy: Set the deceleration time longer. Check the wiring to avoid output short circuit or ground fault. Check if the mechanical brake is set to be activated too early. Lower the stall prevention operation level.
E.OV1 Regenerative overvoltage trip during acceleration	Cause: Overvoltage has occurred during acceleration. Remedy: Set the acceleration time shorter. Use the regeneration avoidance function (Pr. 882 to Pr. 886). Set the Pr. 22 Stall prevention operation level correctly. Set Pr. 154 Voltage reduction selection during stall prevention operation = "11".
E.OV2 Regenerative overvoltage trip during constant speed	Cause: Overvoltage has occurred during constant speed operation. Remedy: Keep the load stable. Use the regeneration avoidance function (Pr. 882 to Pr. 886). Use the brake resistor, brake unit or power regeneration common converter as required. Set the Pr. 22 Stall prevention operation level correctly.
E.OV3 Regenerative overvoltage trip during deceleration or stop	Cause: Overvoltage has occurred during deceleration or at a stop. Remedy: Set the deceleration time longer. Make the brake cycle longer. Use the regeneration avoidance function (Pr. 882 to Pr. 886). Use the brake resistor, brake unit or power regeneration common converter as required.
E.THT Inverter overload trip (electronic thermal O/L relay function)	Cause: The electronic thermal relay function for inverter element protection has been activated. Remedy: Set the acceleration time longer. Adjust the Pr. 0 Torque boost setting. Set the Pr. 14 Load pattern selection setting according to the load pattern. Reduce the load.
E.THM Motor overload trip (electronic thermal O/L relay function)	Cause: The electronic thermal relay function for motor protection has been activated. Remedy: Reduce the load. For a constant-torque motor, set the constant-torque motor in Pr. 71 Applied motor. Set the stall prevention operation level accordingly.
E.FIN Heatsink overheat	Cause: The heatsink has overheated. Remedy: Set the surrounding air temperature to within the specifications. Clean the heatsink. Replace the cooling fan.
E.UVT Undervoltage	Cause: The restart operation is repeatedly unsuccessful because the power supply voltage of the inverter has dropped. Remedy: Investigate the devices on the power supply line such as the power supply itself.
E.ILF Input phase loss	Cause: One of the three phases on the inverter input side has been lost or largely unbalanced. Remedy: Wire the cables properly. Repair a break portion in the cable. Check the Pr. 872 Input phase loss protection selection setting.
E.OLT Stall prevention stop	Cause: The output frequency has dropped to 1Hz as a result of deceleration due to the excess motor load. Remedy: Reduce the load. (Check the Pr. 22 Stall prevention operation level setting.) Check the connection of the IPM motor.
E.SOT Loss of synchronism detection	Cause: Operation has gone out of synchronism or without connecting a motor under IPM control. Remedy: Set the acceleration time longer. Reduce the load. Drive the dedicated IPM motor.
E.BE Brake transistor alarm detection	Cause: A fault has occurred in the brake circuit, such as a brake transistor breakage. (Inverter must be powered off immediately.) Remedy: Replace the inverter.
E.GF Output side earth (ground) fault overcurrent at start	Cause: An earth (ground) fault has occurred on the inverter's output side (detected only at a start). Remedy: Remedy the ground fault portion.
E.LF Output phase loss	Cause: One of the three phases (U, V, W) on the inverter's output side has been lost during inverter operation. Remedy: Wire the cables properly. If the motor capacity is smaller than the inverter capacity, match them.
E.OHT External thermal relay operation	Cause: The external thermal relay connected to the OH signal has been activated. Remedy: Reduce the load and operate less frequently. Reset the relay if necessary (inverter will not restart unless reset).
E.PTC PTC thermistor operation	Cause: Resistance of the PTC thermistor connected between terminal 2 and 10 reached the Pr. 561 level. Remedy: Reduce the load.
E.PE Parameter storage device fault	Cause: Operation of the component where parameters are stored (control circuit board) has become abnormal. Remedy: Please contact your sales representative. If writing frequently, check Pr. 342 Communication EEPROM write selection settings.
E.PUE PU disconnection	Cause: A communication error has occurred between the PU and the inverter. Remedy: Connect the parameter unit cable securely. Check the communication data and settings. Increase the Pr. 122 PU communication check time interval setting.
E.RET Retry count excess	Cause: Operation restart within the set number of retries has failed. Remedy: Eliminate the cause of the error preceding this error indication.
E.CPU CPU fault	Cause: An error has occurred in the CPU and in the peripheral circuits. Remedy: Take measures against noises if there are devices producing excess electrical noises. Contact sales representative if it persists.
E.CDO Output current detection value exceeded	Cause: Output current has exceeded the output current detection level set in the parameter. Remedy: Check the settings of Pr. 150, Pr. 151, Pr. 166, and Pr. 167.
E.IOH Inrush current limit circuit fault	Cause: The resistor of the inrush current limit circuit has overheated. Remedy: Configure a circuit where frequent power ON/OFF is not repeated.
E.AIE Analog input fault	Cause: A voltage (current) has been input to terminal 4 when settings (Pr. 267/Switch) mismatch. Remedy: Give a frequency command by a current input or set Pr. 267 and the voltage/current input switch correctly.
E.OS Overspeed occurrence	Cause: During IPM motor control, the motor speed has exceeded the level set in Pr. 374. Remedy: Set the Pr. 374 Overspeed detection level value correctly.
E.PID PID signal fault	Cause: PID upper limit (FUP), PID lower limit (FDN), or PID deviation limit (Y48) has turned ON. Remedy: Make correct settings for Pr. 131, Pr. 132, and Pr. 553.
E.SAF Safety Circuit Fault	Cause: An internal circuit fault has occurred. Either the contact between terminals S1 and SC or S2 and SC has opened. Remedy: Short across the terminals S1 and SC and the terminals S2 and SC with shortening wires.

How to Read FR-F700PJ Faults via FR Configurator2

To get the most accurate diagnostic data in 2026, connect your PC to the drive using the FR Configurator2 software. This is essential for analyzing the complex loads often found in fan and pump applications.

• Alarm History Analysis: Retrieve detailed data for the last 8 alarms. This includes the exact output voltage, current, and cumulative operation time at the moment the fault occurred.
• Oscilloscope Function: Graph real-time motor performance to detect fluid hammer effects or fan imbalances before they trigger a hard fault.
• Life Diagnosis: The F700PJ has internal counters for capacitor and cooling fan life. Use the software to check if a component is approaching its end-of-life (indicated by “FN” or specific warnings).

Frequently Asked Questions (FAQ)

Q: What is the difference between a Warning and a Fault?
A: A Warning (codes like ‘OL’ for Stall Prevention or ‘PS’ for PID Stop) indicates a limit is being reached or a specific mode is active, but the motor continues to run. A Fault (codes starting with ‘E.’, such as ‘E.OV1’ or ‘E.THT’) acts as a protective trip, immediately cutting output to the motor.

Q: How do I reset a Mitsubishi FR-F700PJ fault?
A: You can reset the drive by pressing the STOP/RESET button on the keypad, cycling the main power (OFF then ON), or by triggering the RES (Reset) digital input terminal.

Q: Where is the fault history stored?
A: The FR-F700PJ stores the last 8 alarm records. You can access them via the operation panel by pressing the MODE button until you reach the Alarm History menu (E.—), or view them via parameters in the FR Configurator2 software.