GRBL 1.1 Alarm 4

GRBL 1.1AlarmPosition is kept

The probe already looked touched (or untouched, for a probe-away move) before probing even started.

Position is kept. The probe cycle stopped before moving. (Hamrun's reading)
What to do
  1. Check the probe isn't already touching: the clip on the bit and the plate under it shouldn't meet before the move.
  2. Touch the clip to the plate by hand and see whether your sender's probe light changes. If it's always on, the probe input is inverted ($6) or the wire is shorted.
  3. Unlock and try the probe again.
What users reported CLAIMED · forum and issue reports, not official
  • Carbide 3D (Shapeoko): The BitZero's magnetic ground clip was left dangling and touching the machine frame. The BitZero and BitSetter share one probe input, so the probe read as already touched. (stated in the thread) Carbide 3D forum, Jun 2024
  • Carbide 3D (Shapeoko): The BitZero's magnet was touching the BitZero plate itself, holding the probe circuit closed. (confirmed in the thread) Carbide 3D forum, Oct 2024
  • Carbide 3D (Shapeoko): The BitSetter button didn't release: its light stayed on, so the controller saw it as still pressed and the second touch was blocked. Carbide support put it down to temperature and replaced it under warranty. (Carbide support's diagnosis, per the thread; one owner's report) Carbide 3D forum, Oct 2024
Official GRBL 1.1 message: “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.” 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 4: The probe already looked touched (or untouched, for a probe-away move) before probing even started.
  • FluidNC Alarm 4: The probe already looked touched (or untouched, for a probe-away move) before probing even started.

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.