What causes FANUC alarm 164?

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 164?

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 164. 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.

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FANUC Controller

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

Alarm 164

Fanuc 164 - Illegal axis command

Alarm 164 occurs when the CNC control encounters an axis command that violates programming rules or syntax. This typically happens when an axis letter is used incorrectly, duplicated in the same block, conflicts with the active plane selection, or when an axis command is formatted improperly for the current G-code mode.

FANUCProgram/G-codeIntermediate5-30 minutes

164

Fanuc 164 - Illegal axis command

ILLEGAL AXIS COMMAND

Root Cause Summary

Alarm 164 occurs when the CNC control encounters an axis command that violates programming rules or syntax. This typically happens when an axis letter is used incorrectly, duplicated in the same block, conflicts with the active plane selection, or when an axis command is formatted improperly for the current G-code mode.

Safety

Verify corrected program or parameters before resuming machining

Causes and Fixes

1
Note the alarm line number displayed on the control screen and locate that block in your part program.
2
Examine the flagged block carefully for any axis letter (X, Y, Z, A, B, C, U, V, W) that appears more than once.
3
Remove the duplicate axis command or split the movement into two separate blocks if both positions are needed sequentially.
4
Reset the alarm, return to program start or the appropriate sequence number, and restart the program in single block mode to verify the correction.
Always verify tool position and work offsets before restarting after program modifications.

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