What causes FANUC alarm 043?

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 043?

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 43. 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 043

Fanuc 43 - Tool length measurement command error

Alarm 043 occurs when the CNC detects an improperly formatted or contextually invalid tool length measurement command (typically G36/G37 or equivalent) in the part program. This is commonly caused by missing parameters, incorrect axis designation, incorrect mode conditions, or attempting tool measurement without proper machine setup or option availability.

FANUCProgram/G-codeIntermediate5-30 minutes

043

Fanuc 43 - Tool length measurement command error

TOOL LENGTH MEASUREMENT COMMAND ERROR

Root Cause Summary

Alarm 043 occurs when the CNC detects an improperly formatted or contextually invalid tool length measurement command (typically G36/G37 or equivalent) in the part program. This is commonly caused by missing parameters, incorrect axis designation, incorrect mode conditions, or attempting tool measurement without proper machine setup or option availability.

Safety

Verify corrected program or parameters before resuming machining

Causes and Fixes

1
Review the program line that triggered the alarm and verify the G36 or G37 command format matches your machine's programming manual (typically G36 Z_; or G37 Z_; format).
2
Confirm all required parameters are present including axis designation (usually Z-axis) and reference position value.
3
Check that only one axis is specified in the measurement command - multiple axes in a single G36/G37 block may cause this error.
4
Verify the command is in a separate block without other G-codes that may conflict with the measurement cycle.

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