So like many other I come here out of frustration. My A1 has been down for weeks as I have been going back and forth with tech support, and to their credit they appear to be trying to help. Any time I run the auto bed leveling I have the extrusion force sensor error, HMS 0300 1800 0001 0003. I have also gotten a pop up window with error 0300-400c 153621.
The strange thing was that when I ran the calibration from the printer itself it ran all the way through. If I run a print without the bed leveling the print fails or looks terrible.
So far support has had me change the TH board, check the usb-c cable several times, and change the extruder unit all together. Still the problem persists. I don’t imagine this is a common occurrence but any help would be appreciated.
Hi,
perhaps your bed is out of tolerance for a bed levelling.
Did you try a tramming : Manual Bed Leveling / Manual Bed Tramming | Bambu Lab Wiki
That link is for the P1/X1. Does it work the same for the A1? I don’t see the instructions in the A1 section of the wiki.
Bad link, sorry.
The link for A1 tramming:
It seems it is not uncommon. I have just assembled my new A1 and have the same problem. Not happy for a new machine to have issues out of the box.
HMS_0300-1800-0001-0004: “The data from extrusion force sensor is abnormal, the sensor should be broken” I submit the sensor should not be broken!
The site recommends “open the back cover of the toolhead”. I’m not happy about pulling apart a new machine.
So my update is that after sending days worth of error logs, I was asked to send more pictures of how the hot end was mounted (probably looking for those mis routed or pinched wires) all of my logs have now been sent past the support desk to R&D.
They are now acknowledging that this may be a main board issue.
update: I removed the back cover as recommended and checked the terminals. Terminals are tight. I had been unable to submit a Tech Ticket myself as I could not upload the ‘log’ as is necessary to get the Ticket to go through. Fortunately I got a real person online in the online help who logged a Ticket for me. The other issue is the printer advises there is an update available but I can’t get it to update despite web connection. Frustrating stuff with a new machine.
Estou com o mesmo problema! Minhas peças estão dando erro constante a cada 10 minutos e ficando com marcas fortes nas linhas. Vi que talvez fosse por causa do nivelamento, mas quando solicito o nivelamento automático está dando erro. Estou extremamente chateada com minhas peças e erros.
Hi,
If you don’t scceed in levelling the bed, perhaps your bed is out of leveling limits.
Just have a try to tramm the bed :
(as said earlier…)
It looks like the main board replacement was the issue. I have had the error reappear 4 times and had 15 error-free prints since the replacement.
Hi, I have the problem after a clog. Is the sensor replacable or is it a replacement board? Thanks
Add me to the list. Brand new A1 printer just received, purchased January 4, 2026, and I’m getting “The data from extrusion force sensor is abnormal, the sensor is probably broken. [0300-1800-0001-0004][130622]” Can’t even home, so the machine is effectively dead in the water. Filed a ticket, but autoreply says customer support is overwhelmed and not to expect a human reply for at least 3 days.
Same here. Very frustrating.
Same error appears to me. I tried everything and still the same error when trying to Home Z axis. If you had this problem too and already fixed it please help me. Im very frustrated and i need to fix it asap. Thank you.
I found the solution on my own. In my case, it was just a faulty USB connection underneath the printer. I’m not a fan of that rather awkward connection design, but at least once it’s finally solid you can forget about it. If/when there’s an A2, I imagine they’ll have something better.
I am also having force extrusion errors. Bambu has had me replace the extruder and the USB C cable with no luck. Has anybody been able to fix this problem?
YES, had the same issues. On mine, the USB cord has a little built in washer-type ring that wanted to stay on the outside of the notch in the casing but needed to be on the inside of it. I had to force it. That 1mm of rubber kept the USB from being fully plugged in.