LogrobotLM

LogrobotLM — AI fault diagnosis for ABB · KUKA · FANUC robots. It reads your robot backup in your browser (never uploaded) and pinpoints the fault. Try it free →

FANUC Alarm FILE-040 — WARN Illegal file access mode

FANUC FILE-040 (“WARN Illegal file access mode”): You tried to read from a write only opened file or tried to write to a read only opened file. First check: Open a file with correct access mode.

Updated 2026-09-17 · LogrobotLM reference

Description

You tried to read from a write only opened file or tried to write to a read only opened file.

Remedy

Open a file with correct access mode.

Related codes

FILE-038WARN File locked by too many tasksFILE-039WARN Directory already existsFILE-041WARN File not lockedFILE-042WARN ( this is an internal code)

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. How this reference is built →