Code 090: REFERENCE RETURN INCOMPLETE
Issue Description & Safety Warning
The Fanuc 16i/18i/21i CNC has triggered a critical REFERENCE RETURN INCOMPLETE alarm. Immediate attention from a qualified operator or maintenance technician is required to prevent secondary damage to the equipment or spoiled parts during the manufacturing cycle. Always ensure standard safety and LOTO procedures are followed before accessing electrical cabinets.
Official Troubleshooting Steps
The reference position return cannot be performed normally because the reference position return start point is too close to the reference position or the speed is too slow. Separate the start point far enough from the reference position, or specify a sufficiently fast speed for reference position return.
Source: Fanuc Series 16i/18i/21i-B Operator's Manual, Appendix G Alarm List (B-63864EN/03)
Last reviewed: 2026-07-01 · Verified against the manufacturer’s official documentation.
About Fanuc 16i/18i/21i CNC Alarms
Fanuc controllers include extensive self-diagnostics that flag or halt the machine when a fault is detected. Error code 090 on the 16i/18i/21i CNC identifies one specific fault condition — its documented cause and the official corrective steps are listed above, sourced from Fanuc's service documentation. Always confirm against the manual for your exact machine configuration and follow LOTO procedures before servicing.
Complete Alarm List: 360 Fanuc 16i/18i/21i CNC codes.
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