Industrial Error Code Fixes

Industrial Fault Codes

362 guides for fault and alarm codes on plant and facility equipment: drives, CNC machines, forklifts, UPS systems, generators, and air compressors. Each guide lists what the code means, the likely causes in order of how often they occur, and the checks to run before you replace parts.

Before you work on any of this equipment, lock out and tag out the power source, wait for DC bus or capacitor discharge per the OEM manual, and verify zero energy with a meter. The OEM manual for your exact model is the final word on code meanings, which can differ between firmware versions.

Jump to: VFD and AC drive (155) · CNC (133) · Forklift (16) · UPS alarms and (7) · Industrial and standby generator (32) · Air compressor (19)

Brand deep dives: VFD fault code guide, CNC error code guide, industrial troubleshooting checklist.

VFD and AC drive fault codes (155)

Overcurrent, overvoltage, undervoltage, ground fault, and overheat trips on variable frequency drives. Most drive faults trace to the motor, the cable, the incoming supply, or cooling, not the drive itself. Check those first.

ABB

Allen Bradley

Yaskawa

Siemens

Danfoss

Schneider

Mitsubishi

Lenze

SEW Eurodrive

Emerson

Fuji

Hitachi

Delta

Vacon

Other brands and general guides

CNC alarm codes (133)

Servo, spindle, encoder, overtravel, and tool changer alarms on CNC controls. Write down the full alarm number and any sub-code before resetting, because many alarms clear on reset and the history is what tells you the cause.

Haas

Fanuc

Mazak

Okuma

Siemens

Heidenhain

Mitsubishi

DMG Mori

Doosan

NUM

Hurco

Other brands and general guides

Forklift fault codes (16)

Electric and IC forklift codes for traction, hydraulics, controllers, and engines. Lock out the truck, discharge the controller per the service manual, and check battery voltage and connectors before replacing modules.

Crown

Raymond

Toyota

Hyster

Yale

Clark

Nissan

Unicarriers

Cat

Jungheinrich

Linde

UPS alarms and fault codes (7)

Battery, overload, bypass, and inverter alarms on UPS systems. Battery age and load level cause most UPS alarms. Large three-phase units should be serviced by qualified technicians.

APC

Eaton

Vertiv

Liebert

Cyberpower

Tripp Lite

Riello

Industrial and standby generator fault codes (32)

Overcrank, low oil pressure, overspeed, and transfer switch faults on standby and prime power generators.

Generac

Kohler

Cummins

Briggs Stratton

Other brands and general guides

Air compressor fault codes (19)

Rotary screw and reciprocating compressor alarms for high discharge temperature, motor overload, and pressure faults.

Atlas Copco

Ingersoll Rand

Kaeser

Quincy

Sullair

Gardner Denver

Other brands and general guides