Toshiba G7 Fault Codes List

Troubleshoot your Toshiba G7 adjustable speed drive with our updated fault code guide. Learn to interpret OC, OL, and EF trips, view the LCD trip history, and reset faults.

Toshiba G7 Fault Codes Reference Table

Below is the complete list of trip codes and alarms. Please refer to this table to match the code on your LCD display with the specific hardware or parameter issue.

Toshiba G7 Drive Fault Codes List

Fault Code and Meaning	Cause and Remedy
CM1 Comm1 Error	Cause: Internal communications error. Remedy: Improperly programmed ASD. Improper communications settings. Improperly connected cables.
CM2 Comm2 Error	Cause: External communications error. Remedy: Check external communication connections. Verify communication settings.
EMG Emergency Off	Cause: Output signal from the ASD is terminated and a brake may be applied if so configured. Remedy: Stop|Reset pressed twice at the EOI. EOFF command received remotely. ASD reset required.
MOFF Main Undervoltage	Cause: Undervoltage condition at the 3-phase AC input to the ASD. Remedy: Check for low 3-phase utility voltage.
OC Over Current	Cause: ASD output current greater than F601 setting. Remedy: Defective IGBT (U, V, or W). ASD output to the motor is connected incorrectly. Disconnect the motor and retry. ASD output phase-to-phase short. The ASD is starting into a spinning motor. Motor/machine jammed. Mechanical brake engaged while the ASD is starting or while running. Accel/Decel time is too short. Voltage Boost setting is too high. Load fluctuations. ASD operating at an elevated temperature.
OH Overheat	Cause: ASD ambient temperature excessive. Remedy: ASD is operating at an elevated temperature. ASD is too close to heat-generating equipment. Cooling fan vent is obstructed. Cooling fan is inoperative. Internal thermistor is disconnected.
OJ Timer	Cause: Run-time counter exceeded. Remedy: Type Reset required; select Clear run timer.
OLI ASD Overload	Cause: Load requirement in excess of the capability of the ASD. Remedy: The carrier frequency is too high. An excessive load. Acceleration time is too short. DC damping rate is set too high. The motor is starting into a spinning load after a momentary power failure. The ASD is improperly matched to the application.
OLM Motor Overload	Cause: Load requirement in excess of the capability of the motor. Remedy: V/f parameter improperly set. Motor is locked. Continuous operation at low speed. The load is in excess of what the motor can deliver.
OLR Resistor Overload	Cause: Excessive current at the Dynamic Braking Resistor. Remedy: Deceleration time is too short. DBR configuration improperly set.
OP Overvoltage	Cause: DC bus voltage exceeds specifications. Remedy: ASD attempting to start into a spinning motor after a momentary power loss. Incoming utility power is above the specified range. Decel time is too short. Voltage spikes at the 3-phase input; install inductive filter. DBR required or DBR resistance value is too high. DBR function is turned off. Overvoltage Stall feature is turned off. System is regenerating. Load instability. Disable the Ridethrough function (F302).
OT Overtorque	Cause: Torque requirement in excess of the setting of F616 or F617 for a time longer than the setting of F618. Remedy: ASD is not correctly matched to the application. F616 or F617 setting is too low. Obstructed load.
POFF Control Undervoltage	Cause: Undervoltage condition at the 5, 15, or the 24 VDC supply. Remedy: Defective Control board. Excessive load on power supply. Low input voltage.
PtSt Reference Point	Cause: Two speed-reference frequency setpoint values are too close to each other. Remedy: Two speed reference frequency setpoints are too close to each other (increase the difference).
UC Undercurrent	Cause: Output current of the ASD is below the level defined at F611 and remains there for the time set at F612. Remedy: Check load coupling (load loss). Check F611 and F612 settings.
Autotune Error Autotune Malfunction	Cause: Autotune readings that are significantly inconsistent with the configuration information. Remedy: A non-3-phase motor is being used. Incorrect settings at F400, F413, or F414. Using a motor that has a significantly smaller rating than the ASD. ASD output cabling is too small, too long, or is being housed in a cable tray with other cables that are producing an interfering EMF. Motor is running during the Autotune function.
Communication Error Comms Malfunction	Cause: System communication failure. Remedy: Communication malfunction. Improper or loose connection. Improper system settings.
CPU Fault Processor Error	Cause: Internal processor error. Remedy: CPU malfunction. Contact Toshiba support.
DC Bus Undervoltage Bus Voltage Low	Cause: DC Bus voltage dropped below limit. Remedy: 3-phase input voltage low. Defective control board. Excessive load on the power supply. Undervoltage/Ridethrough settings require adjustment.
DC Fuse Open Internal Fuse Blown	Cause: Internal DC bus fuse is open. Remedy: Check internal fuses. Check for shorts.
Dynamic Braking Resistor Overcurrent DBR Overcurrent	Cause: ASD inability to discharge the bus voltage during regeneration. Remedy: No dynamic braking resistor (DBR) installed. Deceleration time is too short. Improper DBR setup information. Defective IGBT7 (or IGBT7 ckt.). 3-phase input voltage is above specification.
Earth Fault Ground Fault	Cause: Current leakage to Earth Ground detected. Remedy: Ground fault at the motor. Ground fault at the output of the ASD. Current leakage to Earth Ground.
EEPROM Data Fault Memory Error	Cause: Internal EEPROM malfunction. Remedy: Cycle power. If fault persists, replace control board.
Encoder Loss Signal Missing	Cause: Encoder signal missing while running during closed-loop operation. Remedy: Check encoder connections. Check encoder power supply.
Gate Array Fault Hardware Failure	Cause: Defective Gate Array or Gate Array malfunction. Remedy: Contact service representative.
Input Phase Loss Phase Missing	Cause: 3-phase input to the ASD is low or missing. Remedy: Check incoming power fuses and connections.
Load Drooping Load Error	Cause: Load requirement is in excess of the capabilities of the motor. Remedy: Check load mechanics. Verify motor sizing.
Load End Short Circuit Output Short	Cause: Improper wiring at the ASD output to the motor. Remedy: Check motor wiring for shorts.
Low Current Current Low	Cause: Improper Low Current detection level setting. Remedy: Adjust low current detection parameters.
Option Fault Card Error	Cause: Optional device malfunction. Remedy: Improper system settings (at ASD or optional device). Loose or improper connection.
Output Phase Loss Motor Phase Lost	Cause: 3-phase output from the ASD is low or missing. Remedy: Output current is not within specified limits. Loose or improper ASD-to-motor connection.
Overcurrent During Acceleration Accel OC	Cause: Overcurrent detected while ramping up speed. Remedy: V/f setting needs to be adjusted. Restart from a momentary power outage. The ASD is starting into a rotating motor. ASD/Motor not properly matched. Phase-to-phase short (U, V, or W). Accel time too short. Voltage Boost setting is too high. Motor/machine jammed. Mechanical brake engaged while the ASD is running.
Overcurrent During Deceleration Decel OC	Cause: Overcurrent detected while ramping down speed. Remedy: Phase-to-phase short (U, V, or W). Deceleration time is too short. Motor/machine jammed. Mechanical brake engaged while the ASD is running.
Overcurrent During Run Run OC	Cause: Overcurrent detected at constant speed. Remedy: Load fluctuations. ASD is operating at an elevated temperature.
Over Speed Speed Limit Exceeded	Cause: Result of a motor speed that is greater than the commanded speed when using an encoder for speed control. Remedy: Improper encoder connection or setup information. Defective encoder.
PG Type/Connection Error Encoder Error	Cause: ASD is configured to receive a signal from a shaft-mounted encoder and no signal is being received. Remedy: Disconnection at the Encoder circuit. Motor is stopped and is generating torque via torque limit control. ASD is not configured properly.
Phantom Fault System Fault	Cause: In a multiple ASD configuration a faulted ASD signals the remaining ASDs that a fault has occurred. Remedy: Check other ASDs in the system for the primary fault.
Position Deviation Error Position Error	Cause: Operating in the Position Control mode and the resulting position exceeds the limits of the F631 setting. Remedy: Check position loop settings. Check mechanical linkage.
Sink/Source Setting Error Jumper Error	Cause: Logic setting mismatch. Remedy: Improperly positioned Sink/Source jumper on the control board or on an option device. Sink/Source configuration of an option device is incorrect.
Torque Proving Fault Brake Logic Error	Cause: Torque proving logic failed. Remedy: Lift-First Pulse Count (F743) adjustment required.
Typeform Error Firmware Mismatch	Cause: Firmware information loaded into the Gate Driver board is inconsistent with the device. Remedy: The Gate Driver board has been replaced. The Gate Driver board is defective.
U/V/W Phase Short Circuit Output Short	Cause: Low impedance at the U, V, or W lead of the ASD output. Remedy: Check for short circuit in motor cable or motor windings. Check IGBTs.

 

How to Read G7 Faults via LCD Keypad

The G7’s greatest asset is its user-friendly keypad. In 2026, you don’t necessarily need a laptop to diagnose a trip if you know how to navigate the EOI:

• Trip History: The G7 stores the last 4 faults in its memory. Press the MON (Monitor) button and scroll to the “Trip History” section. It will show the fault code (e.g., Trip 1: OC1) and the sequence in which they occurred.
• Status at Trip: Inside the Trip History menu, you can select a specific fault and press ENT (Enter). This displays the “Status at Trip,” showing the output frequency, current, and voltage at the exact moment the drive failed.
• Monitor Mode: Real-time monitoring allows you to watch the “Input Terminal Status” to see if an external interlock or E-Stop is physically triggering the drive to stop.

General Troubleshooting Steps

Before resetting a major fault on the G7, perform these checks:

1. Overcurrent (OC1/OC2/OC3): The G7 is sensitive to short circuits. OC1 is during acceleration, OC2 during deceleration, and OC3 during run. Disconnect the motor leads and perform a megger test on the motor.
2. Ground Fault (EF1/EF2): “EF” indicates an Earth Fault. This is often caused by moisture in the conduit or compromised motor insulation. Do not repeatedly reset an EF fault, as it can blow the input transistors.
3. Overload (OL1/OL2): OL1 is the Motor Thermal Overload; OL2 is the Drive Inverter Overload. If OL1 occurs, check if the motor cooling fan is clogged. If OL2 occurs, the load may be too heavy for the drive size.

Frequently Asked Questions (FAQ)

Q: What is the difference between “OFF” and a Fault?

A: If the display simply says OFF, the drive is not faulted; it is in a “Ready” state but lacks a Run command. A Fault (like E or OC) will flash the “TRIP” LED and require a manual reset.

Q: How do I reset a Toshiba G7 fault?

A: You can reset the drive using one of these methods:

• Press the STOP/RESET key on the keypad twice.
• Momentarily close the RES (Reset) terminal to CC (Common).
• Cycle the main power supply (Power OFF/ON).

Q: What does the “E” code mean?

A: The E code indicates an “Emergency Off.” This is usually triggered when the drive receives a stop command while in a failure mode, or if the “Emergency Stop” parameter is activated via a digital input. Check your E-Stop buttons and wiring continuity.