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FANUC Alarm PRIO-499Modbus System Error

FANUC PRIO-499 (“Modbus System Error”): Modbus TCP System Error. First check: Turn off the controller, then turn it on again.

Updated 2026-08-29 · LogrobotLM reference

Description

Modbus TCP System Error. A general system failure has occurred.

Remedy · Remède

Turn off the controller, then turn it on again. If the error still occurs, document the events that led to the error and contact your FANUC technical representative.

Frequently asked · Questions fréquentes

What does FANUC alarm PRIO-499 mean?
FANUC PRIO-499 (“Modbus System Error”): Modbus TCP System Error. A general system failure has occurred.
How do you troubleshoot FANUC alarm PRIO-499?
Turn off the controller, then turn it on again. If the error still occurs, document the events that led to the error and contact your FANUC technical representative.

Related codes / Codes liés

Indicative field information — the robot manufacturer's manual and safety procedures always prevail. Never bypass a safety device; apply lockout/tagout (LOTO) before any physical intervention. · Informations indicatives issues du terrain — le manuel du constructeur et ses procédures de sécurité font foi. Ne shuntez jamais un organe de sécurité ; consignez (LOTO) avant toute intervention physique. How this reference is built →