|Error Code Description
|G-code words consist of a letter and a value. Letter was not found.
|Numeric value format is not valid or missing an expected value.
|Grbl '$' system command was not recognized or supported.
|Negative value received for an expected positive value.
|Homing cycle is not enabled via settings.
|Minimum step pulse time must be greater than 3usec
|EEPROM read failed. Reset and restored to default values.
|Grbl '$' command cannot be used unless Grbl is IDLE. Ensures smooth operation during a job.
|G-code locked out during alarm or jog state
|Soft limits cannot be enabled without homing also enabled.
|Max characters per line exceeded. Line was not processed and executed.
|(Compile Option) Grbl '$' setting value exceeds the maximum step rate supported.
|Safety door detected as opened and door state initiated.
|(Grbl-Mega Only) Build info or startup line exceeded EEPROM line length limit.
|Jog target exceeds machine travel. Command ignored.
|Jog command with no '=' or contains prohibited g-code.
|Laser mode requires PWM output.
|Unsupported or invalid g-code command found in block.
|More than one g-code command from same modal group found in block.
|Feed rate has not yet been set or is undefined.
|G-code command in block requires an integer value.
|Two G-code commands that both require the use of the XYZ axis words were detected in the block.
|A G-code word was repeated in the block.
|A G-code command implicitly or explicitly requires XYZ axis words in the block, but none were detected.
|N line number value is not within the valid range of 1 - 9,999,999.
|A G-code command was sent, but is missing some required P or L value words in the line.
|Grbl supports six work coordinate systems G54-G59. G59.1, G59.2, and G59.3 are not supported.
|The G53 G-code command requires either a G0 seek or G1 feed motion mode to be active. A different motion was active.
|There are unused axis words in the block and G80 motion mode cancel is active.
|A G2 or G3 arc was commanded but there are no XYZ axis words in the selected plane to trace the arc.
|The motion command has an invalid target. G2, G3, and G38.2 generates this error, if the arc is impossible to generate or if the probe target is the current position.
|A G2 or G3 arc, traced with the radius definition, had a mathematical error when computing the arc geometry. Try either breaking up the arc into semi-circles or quadrants, or redefine them with the arc offset definition.
|A G2 or G3 arc, traced with the offset definition, is missing the IJK offset word in the selected plane to trace the arc.
|There are unused, leftover G-code words that aren't used by any command in the block.
|The G43.1 dynamic tool length offset command cannot apply an offset to an axis other than its configured axis. The Grbl default axis is the Z-axis.
|Tool number greater than max supported value.
|Alarm Code Description
|Hard limit triggered. Machine position is likely lost due to sudden and immediate halt. Re-homing is highly recommended.
|G-code motion target exceeds machine travel. Machine position safely retained. Alarm may be unlocked.
|Reset while in motion. Grbl cannot guarantee position. Lost steps are likely. Re-homing is highly recommended.
|Probe fail. The probe is not in the expected initial state before starting probe cycle, where G38.2 and G38.3 is not triggered and G38.4 and G38.5 is triggered.
|Probe fail. Probe did not contact the workpiece within the programmed travel for G38.2 and G38.4.
|Homing fail. Reset during active homing cycle.
|Homing fail. Safety door was opened during active homing cycle.
|Homing fail. Cycle failed to clear limit switch when pulling off. Try increasing pull-off setting or check wiring.
|Homing fail. Could not find limit switch within search distance. Defined as 1.5 * max_travel on search and 5 * pulloff on locate phases.
|Homing fail. On dual axis machines, could not find the second limit switch for self-squaring.