GRBL 1.1 Alarm 9

GRBL 1.1AlarmPosition isn't set yet: home first

During homing an axis travelled as far as it's allowed to and never found its limit switch.

Position isn't set yet: home first. Homing didn't finish. (Hamrun's reading)
What to do
  1. Watch which axis keeps moving without stopping: that's the switch to check.
  2. Press that switch by hand and watch the pin state in your sender. No change means wiring or a dead switch; always on means the switch setting is inverted ($5).
  3. Check the axis really reaches the switch: loose pulley, binding axis, or max travel ($130–$132) set shorter than the machine.
  4. If the machine has no switch on an axis, don't home that axis (homing cycle settings) instead of forcing it.
  5. Settings sent by another program can be the culprit: compare the controller's $$ settings with the machine maker's.
What users reported CLAIMED · forum and issue reports, not official
  • Carbide 3D (Shapeoko): The homing switch was mounted too far from the axis rail to be triggered. Moving the switch fixed it. (confirmed in the thread) Carbide 3D forum, Aug 2025
  • Carbide 3D (Shapeoko): Loose stepper pulleys (set screws not seated, one should sit on the shaft's flat) and unadjusted eccentric nuts or tight spots. Worth checking, but that thread's actual fix was the switch position. (suggested, not the confirmed fix) Carbide 3D forum, Aug 2025
  • Carbide 3D (Shapeoko): The wrong machine configuration was sent to the controller: the belt-Z setting on a Z-Plus machine, so Z drove down, away from its switch. (confirmed in the thread) Carbide 3D forum, Aug 2025
  • Carbide 3D (Shapeoko): A binding Z axis: dry, unlubricated Z-Plus rails stopped the axis reaching its switch. Lubricating them fixed it; a loose belt, pulley or coupler was also mentioned. (confirmed in the thread by a second owner) Carbide 3D forum, Dec 2023
  • Carbide 3D (Shapeoko): The homing switch connector at the controller wasn't seated. The switch didn't light until it was unplugged and plugged back in. (confirmed in the thread) Carbide 3D forum, Jan 2025
  • Carbide 3D (Shapeoko): Carbide Motion shows this alarm as HM009. Its message points to a mechanical problem jamming an axis, or a homing switch that isn't working. (quoted in the thread) Carbide 3D forum, Mar 2025
  • The limit switches were inverted (optical switches that output high when triggered). Setting $5=1 to invert them fixed homing. (confirmed in the thread) LightBurn forum, Feb 2023
  • The firmware homed Z first (HOMING_CYCLE_0 set to Z) on a machine with no Z homing switch. Removing Z from the homing cycle in the firmware config fixed it. (confirmed in the thread) LightBurn forum, Jan 2024
  • A rotary attachment has no home or limit switch (it can turn round and round). The fix given: turn off Auto-Home, set $22=0 and $20=0, and use Current Position. (stated in the thread) LightBurn forum, Mar 2026
Official GRBL 1.1 message: “Homing fail. Could not find limit switch within search distances. Try increasing max travel, decreasing pull-off distance, or check wiring.” source

Got a different message?

Paste it into the decoder. Hamrun's editor checks your G-code before you run it, so a toolpath that leaves the machine's travel or a missing feed rate is caught before the machine stops.

Related codes

  • grblHAL Alarm 9: During homing an axis travelled as far as it's allowed to and never found its limit switch.
  • FluidNC Alarm 9: During homing an axis travelled as far as it's allowed to and never found its limit switch.
  • GRBL 1.1 Alarm 6: Homing was interrupted by a reset before it finished.
  • GRBL 1.1 Alarm 7: The safety door was opened during homing.
  • GRBL 1.1 Alarm 8: After touching a limit switch, the machine backed off but the switch still read as pressed.
  • GRBL 1.1 Alarm 10: On a machine with two motors on one axis, the second limit switch wasn't found when squaring.

Official text copied from the GRBL 1.1 source on 2026-11-01. Steps and the position answer are Hamrun's reading unless marked “firmware says”. User reports are labelled CLAIMED.