grbl/doc/csv/alarm_codes_en_US.csv

1	Alarm Code in v1.1+	Alarm Message in v1.0-	Alarm Description
2	1	Hard limit	Hard limit has been triggered. Machine position is likely lost due to sudden halt. Re-homing is highly recommended.
3	2	Soft limit	Soft limit alarm. G-code motion target exceeds machine travel. Machine position retained. Alarm may be safely unlocked.
4	3	Abort during cycle	Reset while in motion. Machine position is likely lost due to sudden halt. Re-homing is highly recommended.
5	4	Probe fail	Probe fail. Probe is not in the expected initial state before starting probe cycle when G38.2 and G38.3 is not triggered and G38.4 and G38.5 is triggered.
6	5	Probe fail	Probe fail. Probe did not contact the workpiece within the programmed travel for G38.2 and G38.4.
7	6	Homing fail	Homing fail. The active homing cycle was reset.
8	7	Homing fail	Homing fail. Safety door was opened during homing cycle.
9	8	Homing fail	Homing fail. Pull off travel failed to clear limit switch. Try increasing pull-off setting or check wiring.
10	9	Homing fail	Homing fail. Could not find limit switch within search distances. Try increasing max travel, decreasing pull-off distance, or check wiring.