HMS 1A00-3000-0001-0041: Hotend Presence Sensor Is Short-Circuit
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HMS 1A00-3000-0001-0041 means the toolhead presence detection sensor reads as short-circuit, and Bambu offers the same two fixes as for the open version: reconnect the sensor cable or replace the sensor. A short is an unintended connection rather than a missing one, which points at damaged insulation more than at a loose plug.
The open-circuit and short-circuit versions look identical on screen and lead to different places.
Where to buy
Why a short points at the cable, differently
An open circuit is usually a connector that has worked loose. A short is usually two conductors touching, which happens where insulation has been pinched, chafed through, or trapped during a reassembly. Follow the run and look for the point where it passes something hard or bends tightly.
Check the connector for a bent pin
A pin pushed sideways during reseating can bridge to its neighbour, which reads as a short with no damage visible along the cable at all. Unseat the connector and look into it with a light before concluding anything about the wiring. The rack has its own position sensor with the same failure modes, covered in HMS 1A00-3300-0001-0040.
Then meter it
Continuity between the two sides of the sensor circuit confirms a short and tells you whether it is in the cable or in the sensor body. That is a two-minute test and it decides which part to buy. The same method applied to other printer sensing is in 3D printer thermistors.
How HMS 1A00-3000-0001-0041 differs from the open fault
The open version is HMS 1A00-3000-0001-0040, where reseating the connector clears most cases. Here reseating is less likely to help, and inspecting the cable run is where the time is best spent. Reading the last digit of the code is the whole difference.
What it stops you doing
Swapping depends on this sensor, so tool changes are out until it is fixed. A hotend reported as missing when you can see it is the same symptom either way, and the mechanical version of that is HMS 1A00-0100-0002-0023.
HMS 1A00-3000-0001-0041 FAQ
Is a short worse than an open?
Not worse, but less likely to be a simple reseat. Budget for a cable or a sensor.
Can I print single-tool?
Generally yes, with swapping unavailable.
Did a repair cause it?
Often. A cable trapped during reassembly is the classic origin of a short.
Which part do I order?
Whichever the continuity test implicates. Guessing costs a part you did not need.
LayerWalker
Print defect diagnosis, calibration procedures and parts that actually fit. Corrections welcome through the contact page.
