HMS 0300-2600-0001-000B: left nozzle presence detection failed
LayerWalker is a participant in the Amazon Services LLC Associates Program. We may earn a commission when you buy through links on our site, at no extra cost to you.
HMS 0300-2600-0001-000B means the printer looked for the left nozzle and could not confirm it. On a dual-nozzle machine that is a safety gate: it will not heat and move a toolhead whose state it cannot establish. The two possibilities are a nozzle that is genuinely absent and one that is fitted but sitting outside the sensor’s working range.
Affected machines: H2 and X2D. The check runs at start-up and before calibration, so the code appears when you try to begin a print rather than during one. That timing is itself a clue: it points at something that changed while the machine was off, which is usually maintenance.
Where to buy
The seat matters more than the thread
Most people tighten a nozzle until it feels right and assume that is enough. What actually decides detection is whether the nozzle flange is flat against its seat, and a ring of baked purge residue under that flange holds it a few tenths of a millimetre high while still feeling perfectly tight.
So the useful habit is cleaning the seat, not just the nozzle. Every nozzle change, wipe the landing face before the new one goes on, and most instances of this code never happen.
The second thing to check is the connector. A hotend that is mechanically home but electrically half-connected reads as absent, and toolhead connectors on these machines are easy to misalign in a confined space.
Printer refuses to start and reports that the left nozzle is not detected
Nozzle missing, not fully seated, residue in the seat, or a failed detection sensor
- Power off and let both hotends cool completely.
- Confirm a left nozzle is fitted and that it is the correct type for your machine.
- Remove it and clean both the nozzle flange and the seat it lands on.
- Refit it fully home and square, tightening at the temperature your machine’s procedure specifies.
- Reseat the left toolhead connector and power up, letting the start-up check run.
- If detection still fails with a clean, correctly fitted nozzle, the sensor has failed and the hotend assembly is the replacement.
Do not look for a way to skip the check. It exists so the machine never heats and moves a toolhead in an unknown state, and there is no version of this fault where bypassing it is the right answer.
The single-nozzle version of this fault is nozzle presence detection failed, and the weak-signal version is low signal on the left eddy sensor. Our page on the hotend covers the assembly, and the troubleshooting index covers the rest.
HMS 0300-2600-0001-000B FAQ
The nozzle is fitted. Why is it not detected?
Fitted and seated are different. Clean the seat and refit it fully home, then retry.
Does nozzle material matter?
Yes. Steel and brass read differently, so recalibrate after changing material.
Can I print on the right nozzle only?
Not until the check passes. The machine will not start with a toolhead in an unknown state.
How often should I clean the seat?
Every nozzle change. It takes a minute and prevents most of these.
LayerWalker
Print defect diagnosis, calibration procedures and parts that actually fit. Corrections welcome through the contact page.
