Mitsubishi FR-E700 Fault Codes: Meanings & Checks

Quick answer

An FR-E700 that trips shuts off its output, sends its fault signal and shows the fault on the operation panel as E. and a short code – for example E.OC1. Warnings such as OL and TH and the FN fan alarm don't stop the output; UV shuts the output off until the supply recovers. The manual says a warning leads to a fault if nothing is done. Find the code below, fix the cause, make sure the start signal is off, then reset with the STOP/RESET key, the RES input or a power cycle.

Jump to a code:

E.OC1
E.OC2
E.OC3
E.OV1
E.OV2
E.OV3
E.THT
E.THM
E.FIN
E.ILF
E.OLT
E.GF
E.LF
E.OHT
E.BE
E.SAF
E.PE
E.PUE
E.RET
E.CPU
E.5
E.6
E.7
E.AIE
E.IOH
E.USB
E.OP1
OL
UV
TH
PS
SA
FN

Safety first: lock out and tag out the inverter and the machine before you open the inverter or touch the wiring, and follow Mitsubishi Electric's precautions in the manual. The smoothing capacitors stay charged after power is removed: the manual says to wait at least 10 minutes, check that the operation panel display is off; then a qualified person, with a properly rated meter checked on a known source before and after, confirms that the voltage between main circuit terminals P/+ and N/– is 30 V DC or less – a dark display alone doesn't mean it's safe. If the panel shows EV (the inverter is running on an external 24 V supply), switch that supply off too. Never bypass the safety stop inputs (S1, S2) or any other safety circuit, and never switch off a fault or raise the retry count to keep a machine running – the retry function restarts the motor by itself. Only qualified personnel should work on inverters, and any measurement on energized equipment follows your site's live-work and arc-flash rules.

Reading and resetting an FR-E700 fault

Note the code. The operation panel's faults history mode shows the past eight faults, each with the output frequency, current, voltage and energization time when it happened. Er.CL clears the history.
Look it up in the table below or in the manual, and fix the cause first – a fault whose cause is still there comes straight back.
Reset it: turn the start signal (STF / STR) off first – the manual warns that a reset with it on restarts the motor at once – then press STOP/RESET, turn on the RES signal for more than 0.1 s, or switch the power off and back on once the panel has gone dark.
Watch the restart. If the same code returns, go back through the checks before resetting again.

The table follows the Instruction Manual (Basic) for the FR-E700 safety stop (SC) models; the Instruction Manual (Applied) for the CC-Link (NC) models describes the same E.OC, E.OV, E.TH and E.FIN codes. Other FR-E700 versions have their own manuals and some codes depend on the model and its options, so check the manual for your inverter's model. Codes marked “Off in the initial setting” only appear once their function has been turned on.

Common FR-E700 fault codes

This list covers the codes technicians run into most often, not every code. The manual has the complete list and the full corrective actions.

Code	What it means	Likely causes	First checks
E.OC1Overcurrent trip during accelerationFault	Output current went over the trip level while the motor was accelerating.	Acceleration time too short for the load A short or ground fault on the output wiring or in the motor Starting into a coasting motor, or Pr.3 [Base frequency] at 60 Hz for a 50 Hz motor	Lengthen Pr.7 [Acceleration time] With power locked out, check the output wiring and the motor for a short or ground fault If it trips at every start, the manual says to try with the motor disconnected; still tripping points to the inverter
E.OC2Overcurrent trip during constant speedFault	Output current went over the trip level while running at a steady speed.	A sudden load change or a jam A short or ground fault on the output side Starting into a motor that is still coasting	Check the load and the machine for jams With power locked out, check the output wiring and the motor Review Pr.22 [Stall prevention operation level] and the fast-response current limit (Pr.156)
E.OC3Overcurrent trip during deceleration or stopFault	Output current went over the trip level while slowing down or stopped.	Deceleration time too short A motor brake closing too early A short or ground fault on the output side	Lengthen Pr.8 [Deceleration time] Check when the mechanical brake engages With power locked out, check the output wiring and the motor
E.OV1Regenerative overvoltage trip during accelerationFault	The DC bus voltage went too high while the motor was accelerating.	A load that drives the motor as it speeds up, for example lowering on a hoist Pr.22 [Stall prevention operation level] set wrong	The manual suggests a shorter acceleration time here Use the regeneration avoidance function (Pr.882, Pr.883, Pr.885, Pr.886) Check the Pr.22 setting
E.OV2Regenerative overvoltage trip during constant speedFault	The DC bus voltage went too high while running at a steady speed.	The load driving the motor (regeneration) A load that swings or changes suddenly	Keep the load steady Use the regeneration avoidance function Add a brake resistor or brake unit where the load keeps regenerating
E.OV3Regenerative overvoltage trip during deceleration or stopFault	The DC bus voltage went too high while slowing down or stopped.	Deceleration time too short for the load's inertia Braking too often	Lengthen the deceleration time to suit the load Make the braking cycle longer, or use regeneration avoidance Add a brake resistor, brake unit or power regeneration converter (FR-CV) if needed
E.THTInverter overload trip (electronic thermal O/L relay function)Fault	The inverter's electronic thermal protection for its own output transistors tripped.	Load too heavy for the inverter Acceleration too short or torque boost too high Load pattern setting wrong, or a hot enclosure	Reduce the load or lengthen the acceleration time Check Pr.0 [Torque boost] and Pr.14 [Load pattern selection] Keep the surrounding air within the inverter's rating; a reset clears the thermal count
E.THMMotor overload trip (electronic thermal O/L relay function)Fault	The inverter's electronic thermal protection for the motor tripped.	Motor overloaded Pr.9 [Electronic thermal O/L relay] not matching the motor A constant-torque motor run with a standard-motor setting	Reduce the load and let the motor cool; a reset clears the thermal count Check Pr.9 against the motor's rated current For a constant-torque motor, set it in Pr.71 [Applied motor]
E.FINHeatsink overheatFault	The heatsink got too hot.	Surrounding air too hot A clogged heatsink A failed cooling fan	Keep the surrounding air within the rating With power locked out, clean the heatsink Replace the cooling fan if it has stopped (see FN)
E.ILFInput phase lossFaultActive only when Pr.872 = 1; check your setting	One of the three input phases is missing, or the phases are badly unbalanced.	A blown fuse or an open breaker pole A broken or loose input cable A badly unbalanced supply	With power locked out, check fuses, terminals and the input cables Checking the supply while it runs is live work for a qualified electrician, or use a power-quality recorder Pr.872 [Input phase loss protection selection] = 1 turns this check on (the Applied manual's initial value); 0 turns it off
E.OLTStall prevention stopFault	Stall prevention brought the output down to 1 Hz because the load was too heavy.	Motor overloaded or the machine jammed Pr.22 [Stall prevention operation level] set too low	With power locked out, check that the machine turns freely Reduce the load Check the Pr.22 setting
E.GFOutput side earth (ground) fault overcurrent at startFaultOff in the initial setting	A ground fault on the output side was found when the inverter started.	Damaged motor cable insulation A motor winding with a fault to ground Moisture in the motor, the terminal box or the conduit	With power locked out, find the grounded part of the motor or its cable Locked out, a qualified person disconnects the motor leads before an insulation check (common practice); the manual warns never to megger the inverter's control circuit Fix the grounded part before resetting
E.LFOutput phase lossFault	One of the output phases (U, V, W) was lost while the inverter was running.	An open conductor or a loose terminal to the motor A motor much smaller than the inverter Starting into a coasting motor	With power locked out, check the motor wiring end to end Use a motor that matches the inverter capacity Start only after the motor stops, or use the restart (flying start) function
E.OHTExternal thermal relay operationFaultOff in the initial setting	A thermal relay or motor thermostat wired to the OH input opened.	The motor overheating from overload or heavy duty A loose wire on the OH input	Reduce the load and how often it runs Find the device wired to the OH input and why it opened The inverter needs a reset even after the relay closes again
E.BEBrake transistor alarm detectionFault	The inverter found a fault in its brake circuit, such as a failed brake transistor.	A brake transistor failure inside the inverter	The manual says to switch the inverter's power off at once Its remedy is replacing the inverter
E.SAFSafety circuit faultFault	A safety circuit fault, or the S1–PC or S2–PC safety stop connection opened.	A safety device (relay module, door switch, e-stop) opened the circuit A broken or loose wire on S1, S2 or PC	Never jumper S1 or S2 on a machine that uses the safety stop function Check the safety relay module and the S1 / S2 / PC wiring Mitsubishi's safety stop function manual (BCN-211508-004) has the causes
E.PEParameter storage device faultFault	The part of the control board that stores the parameters stopped working normally.	A memory fault on the control board Very frequent parameter writes over communication	The manual's remedy is contacting your Mitsubishi sales representative For frequent writes over communication, Pr.342 = 1 writes to RAM only (lost at power-off)
E.PUEPU disconnectionFault	Communication with the parameter unit, or RS-485 on the PU connector, was lost.	A loose or broken PU cable Communication interval or error count exceeded	Reconnect the parameter unit cable Check the communication data and settings Check Pr.122 [PU communication check time interval]
E.RETRetry count excessFaultOff in the initial setting	The retry function could not restart the inverter within the set number of tries.	The fault behind the retries is still there	Retry restarts the motor on its own: remove the start signal before working on the machine Find and fix the fault that came before this one Never raise the retry count (Pr.67) to ride over a fault
E.CPU / E.5 / E.6 / E.7CPU faultFault	An error in the CPU or the circuits around it.	Electrical noise near the inverter A connection between terminals PC and SD (E.6, E.7) An internal fault	Deal with noise sources near the inverter Check the connection between terminals PC and SD If it stays, the manual's remedy is contacting your Mitsubishi sales representative
E.AIEAnalog input faultFault	Terminal 4 got a signal while Pr.267 and the voltage / current input switch were set differently.	Pr.267 [Terminal 4 input selection] and the input switch don't match A voltage signal wired to an input set for current, or the reverse	Set Pr.267 and the switch to match the signal Or give the frequency command as a current
E.IOHInrush current limit circuit faultFault	The resistor in the inrush current limit circuit overheated.	Power switched on and off too often	Use a circuit that doesn't cycle the power often If it continues, the manual's remedy is contacting your Mitsubishi sales representative
E.USBUSB communication faultFault	USB communication was broken for longer than the time set in Pr.548.	A loose or removed USB cable Check interval too short	Reconnect the USB cable Check Pr.548 [USB communication check time interval]
E.OP1Communication option faultFault	A communication error on the line of a communication option.	A loose option or a damaged network cable Option settings wrong Terminating resistors missing	Check the option's settings Seat the option and check the cables Check the terminating resistors
OLStall prevention (overcurrent)Warning	Overcurrent stall prevention is working: the inverter holds back the frequency to limit the current.	Load too heavy, or acceleration / deceleration too fast Torque boost too high	Lengthen the acceleration / deceleration times Reduce the load; change Pr.0 [Torque boost] in 1 % steps Check Pr.22 [Stall prevention operation level]
UVUndervoltageWarning	The supply fell below about 115 V AC (230 V AC on 400 V models); the output is off until it recovers.	A low or dipping supply A lost phase or a loose supply connection	Read the DC bus on the panel first: Pr.52 = 8 shows the converter output voltage Checking the supply while it runs is live work for a qualified electrician, or use a power-quality recorder Look at the devices on the supply line
THElectronic thermal relay function prealarmWarning	The electronic thermal value reached 85 % of the Pr.9 setting; a trip follows if it keeps rising.	A heavy load or running too often Pr.9 [Electronic thermal O/L relay] set wrong	Reduce the load and how often it runs Check Pr.9 against the motor
PSPU stopWarning	STOP/RESET on the operation panel was pressed while the inverter was in External operation.	Someone pressed STOP/RESET at the panel	Turn the start signal off, then release with the PU/EXT key
SASafety stopWarning	The safety stop function is active and the output is shut off.	A safety device opened S1 / S2 A broken wire on S1, S2 or PC	Find which safety device opened and why before restarting Never jumper S1 or S2 to get a machine running If SA stays with both inputs closed, the manual points to an internal failure
FNFan alarmAlarm	The cooling fan stopped or slowed down while it should be running.	A worn or blocked fan	With power locked out, check the fan for blockage For a failed fan, the manual says to contact your Mitsubishi sales representative

The name is the manual's own name for the code; the code is what the operation panel shows. A warning or an alarm doesn't trip the inverter or send the fault signal. OL and TH don't stop the output; UV shuts the output off until the supply recovers, and during SA the safety stop holds it off. Other error messages, warnings and faults in the same list that this page doesn't cover: oL, RB, MT, EV, E.OPT, E.1, E.PE2, E.13, E.MB4–E.MB7, Er1–Er4, Err., HOLD, LOCD – see the manual for those.

Sources: Mitsubishi Electric, FR-E700 Instruction Manual (Basic), FR-E720-0.1KSC to 15KSC, FR-E740-0.4KSC to 15KSC, FR-E720S-0.1KSC to 2.2KSC, IB(NA)-0600458ENG-A (February 2011) – chapter 8, Troubleshooting: Reset method of protective function and List of fault displays; Mitsubishi Electric, FR-E700 Instruction Manual (Applied), CC-Link communication function models FR-E720-0.1KNC to 15KNC, FR-E740-0.4KNC to 15KNC, FR-E720S-0.1KNC to 2.2KNC, IB(NA)-0600402ENG-A (November 2011) – monitor description list (Pr. 52) and the retry function (Pr. 65, Pr. 67 to Pr. 69), read on October 17, 2026.

Meanings, causes and checks are summarized in our own words. The manuals are the reference: they have every code, the full corrective actions and the safety instructions. A newer revision of a manual may add codes, so check the current revision for your drive.

FR-E700 inverters in stock

Mitsubishi FR-E700 (FR-E720, FR-E740) part numbers on our shelves right now. Every item is photographed, so check the nameplate – catalog number and series – against the drive you're replacing.

FR-E720-0.1KNCMitsubishi Electric FR-E720-0.1KNC 0.8-1.5A 3PH AC200-240V 50/60HZ 0.2-400HZ
FR-E740-3Mitsubishi FR-E740-3. 7K 15. 1A 3PH AC380-480V 50/60Hz
FR-E740-120-NAMitsubishi FR-E740-120-NA Inverter VFD AC Drive 7.5HP 16.8A 3PH 380-480V E700
FR-E740-0Mitsubishi FR-E740-0. 75K 4.1A 3PH AC380-480V 50/60Hz
FR-E740-095-NAMitsubishi FR-E740-095-NA E700 Inverter VFD Drive 9.5A 3PH 380-480V 50/60Hz
FR-E740-120SC-NAMitsibishi Electric FR-E740-120SC-NA E700 16.8A 3PH AC380-480V50/60Hz Inverter
FR-E740-3.7KMitsubishi FR-E740-3.7K Inverter VFD 3.7kW 380-480VAC 3PH 15.1A 50/60Hz Drive
FR-E740-300SC-NAFR-E740-300SC-NA NEW MITSUBISHI FRE740300SCNA Inverter

Fault won't clear?

When the checks point to the drive itself – the manual's “replace the inverter” or “contact your sales representative” – send us the fault code and the catalog number from the nameplate. We check our shelves and our sourcing network and reply with a written quote. Purchase orders are welcome; payment is due before we ship.

Frequently asked questions

How do I reset a fault on a Mitsubishi FR-E700?

Fix the cause first and turn the start signal off – a reset with the start signal on restarts the motor at once. Then press STOP/RESET on the operation panel, turn on the RES signal for more than 0.1 s, or switch the power off and on again after the panel goes dark. A reset also clears the electronic thermal count and the retry count.

What does E.OC1 mean on a Mitsubishi FR-E700?

E.OC1 is the overcurrent trip during acceleration: output current went over the trip level while the motor sped up. Lengthen the acceleration time and check the output wiring and the motor for a short or a ground fault. E.OC2 is the same trip at constant speed and E.OC3 during deceleration or at a stop.

What is the difference between a fault, a warning and an alarm on an FR-E700?

A fault (E. and a code) shuts the inverter's output off and sends the fault signal until it is reset. Warnings and the FN fan alarm send no fault signal. OL and TH don't stop the output, but UV shuts it off until the supply recovers, PS follows a STOP/RESET press and SA is the safety stop. A warning that is ignored can turn into a fault.

Where can I see which faults an FR-E700 had?

In the operation panel's faults history mode: the past eight faults, each with the output frequency, current, voltage and energization time when it happened. Er.CL clears the history.

Can you supply a replacement FR-E700 inverter?

Send the model from the rating plate (for example FR-E740-...) and the fault code through our quote form. We check our shelves and our sourcing network and reply with a written quote.

Mitsubishi FR-E700 fault codes: what they mean and what to check first

Quick answer

Reading and resetting an FR-E700 fault

Common FR-E700 fault codes

FR-E700 inverters in stock

Fault won't clear?

Frequently asked questions

Send us the fault code

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