GRBL Error Codes

Error Code

Error Message

Error Description

1

Expected Command Letter

G-code words consist of a letter and a value. Letter was not found.

2

Bad Number Format

Missing the expected G-code word value or numeric value format is not valid

3

Invalid Statement

Grbl ‘$’ system command was not recognized or supported.

4

Value < 0

Negative value received for an expected positive value.

5

Homing Disabled

Homing cycle failure. Homing is not enabled via settings.

7

EEPROM Read Fail

An EEPROM read failed. Auto-restoring affected EEPROM to default values.

8

Not Idle

Grbl ‘$’ command cannot be used unless Grbl is IDLE. Ensures smooth operation during a job.

9

G-Code Lock

G-code commands are locked out during alarm or jog state.

10

Homing Not Enabled

Soft limits cannot be enabled without homing also enabled.

11

Line Overflow

Max characters per line exceeded. File most likely formatted improperly

14

Line Length Exceeded

Build info or startup line exceeded EEPROM line length limit. Line not stored.

15

Travel Exceeded

Jog target exceeds machine travel. Jog command has been ignored.

17

Setting Disabled

Laser mode requires PWM output.

20

Unsupported Command

Unsupported or invalid g-code command found in block. This usually means that you used the wrong Post-Processor to make your file, or that some incompatible code within needs to be manually deleted.

21

Modal Group Violation

More than one g-code command from same modal group found in block.

22

Undefined Feed Rate

Feed rate has not yet been set or is undefined.

23-38

Invalid G-code

Error codes 23-38 all give different reasons for a file failing. To look up further, google "GRBL Error Code [Insert Number] for more information.