HMS 0300-2600-0001-0001: low signal on the left extruder eddy sensor
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HMS 0300-2600-0001-0001 means the eddy current sensor on the left extruder is returning a weak signal. On a dual-nozzle machine you have something most printers cannot offer: a second, identical sensor a few centimetres away. Before assuming anything has failed, compare the two, because a machine-wide problem and a left-side problem need different answers.
Affected machines: H2 and X2D. The sensor is what makes touchless nozzle detection and levelling possible, so a weak reading shows up as levelling that fails or produces a mesh that makes no sense, rather than as a print that stops halfway.
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Three causes, in the order worth checking
Distance. A left nozzle that is not fully home sits further from its sensor than the calibration assumed, and the signal falls off quickly with distance. Remove it, clean the seat, refit it square and fully home.
Contamination. Residue on the sensor face does not always strengthen the reading; a layer of carbonised filament can weaken it too. Clean gently with isopropyl alcohol on a soft cloth.
The sensor. Only after the first two. If the left reads weak while the right reads normally with both nozzles correctly fitted, the left sensor is the odd one out, and on these machines that means a toolhead assembly rather than a discrete part.
Left nozzle detection or bed levelling fails, and the printer reports a low sensor signal
Nozzle not fully seated, residue on the sensor face, or a failing sensor
- Power off and let both hotends cool completely.
- Remove the left nozzle, clean its seat and threads, and refit it fully home and square.
- Clean the left sensor face with isopropyl alcohol on a soft cloth, without scraping it.
- Reseat the left toolhead connector, checking for a pin that is not level with its neighbours.
- Run the machine’s calibration so both sensors are baselined against the nozzles actually fitted.
- Compare the left and right readings. If only the left is weak with everything clean and seated, the sensor is the fault.
Tighten the nozzle at the temperature your machine’s procedure specifies. A nozzle tightened cold loosens as the block expands, and a nozzle that has backed off by half a turn is the most common version of a weak signal.
The right-hand equivalent is right eddy sensor frequency too low, and the detection failure is left nozzle presence detection failed. Our page on the hotend covers the assembly, and the troubleshooting index covers the rest.
HMS 0300-2600-0001-0001 FAQ
Is a weak signal the same as no signal?
No. No signal is a different code. Weak means the sensor sees something, just not clearly enough to trust.
Can I print on the right nozzle meanwhile?
Levelling uses both sides on these machines, so treat the first layer as unreliable until it is fixed.
Why does the right side read fine?
Because the problem is local to the left: its nozzle seating, its sensor face or its sensor.
Is the sensor sold separately?
No. It is part of the toolhead, which is why a confirmed failure means an assembly.
LayerWalker
Print defect diagnosis, calibration procedures and parts that actually fit. Corrections welcome through the contact page.
