What causes FANUC alarm 259?

Part program contains an illegal G-code or M-code combination for this alarm type. Missing or incorrect address word in the program block. Axis or parameter value out of range for the commanded function. Required option not enabled on this CNC for the commanded function. Conflict between active modal states and the commanded function.

How do I fix FANUC alarm 259?

1. Note the block number shown on the alarm screen and locate that block in the program. 2. Review the command in that block against the Fanuc programming manual for alarm 259. 3. Check for missing address words, incorrect values, or conflicting G-code combinations. 4. Verify any required CNC options are enabled if using advanced functions. 5. Correct the program and verify the fix before restarting machining.

axismd.ai

FANUC Controller

Program/G-code · Intermediate · 5-30 minutes

Alarm 259

Fanuc 259 - Tool life management error

Alarm 259 occurs when the tool life management system detects an error in the tool data, tool group configuration, or related M-code/G-code commands. This typically happens when the part program references non-existent tool groups, attempts invalid tool life operations, or when tool life data is corrupted or improperly configured.

FANUCProgram/G-codeIntermediate5-30 minutes

259

Fanuc 259 - Tool life management error

TOOL LIFE MANAGEMENT ERROR

Root Cause Summary

Alarm 259 occurs when the tool life management system detects an error in the tool data, tool group configuration, or related M-code/G-code commands. This typically happens when the part program references non-existent tool groups, attempts invalid tool life operations, or when tool life data is corrupted or improperly configured.

Safety

Verify corrected program or parameters before resuming machining

Causes and Fixes

1
Identify the N-block number where the alarm occurred and review the tool call (T-code) or tool life management command in that line.
2
Access the Tool Life Management screen (OFFSET or TOOL LIFE menu, varies by control model) and verify the tool group number called in the program actually exists.
3
Check that the tool group contains at least one registered tool with valid tool number and life count data.
4
If tool group is missing, create it with proper tool assignments, or correct the program to reference an existing valid tool group number.

Service Recommended confidence

Seeing Multiple Alarms?

Seeing another alarm with this one? Enter the code.

Get machine-aware diagnosis

AxisMD logs alarms against your actual machines, tracks patterns, and gives AI context your manual doesn't have.

Start free

Was this guide helpful?

Always verify with your machine manual or a certified technician before performing service procedures.