HMS 0300 0300
Bambu Lab 3D Printer
Severity: CriticalWhat Does This Error Mean?
HMS 0300 0300 means the nozzle heater is not reaching the target temperature within the expected time. The heater cartridge may be failing, or there is a connection issue. Check the hotend assembly and heater connection.
Affected Models
- Bambu Lab X1 Carbon
- Bambu Lab X1
- Bambu Lab P1S
- Bambu Lab P1P
- Bambu Lab A1
Common Causes
- Heater cartridge failing or burned out
- Hotend not fully seated — heater not making contact
- Excessive cooling from part cooling fan hitting the hotend
- Printing in a very cold environment
- Power delivery issue to the heater
How to Fix It
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Re-seat the hotend assembly.
Remove and reinstall the hotend, making sure it clicks fully into place.
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Check if the hotend heats at all.
Start a preheat. If the temperature does not rise at all, the heater is dead. If it rises slowly, there may be a poor connection.
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Try a different hotend assembly if available.
Bambu Lab hotends are modular. Swapping in a known good one confirms whether the old one is faulty.
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Contact Bambu Lab support for a replacement hotend.
If the hotend is within warranty, Bambu Lab will replace it.
Frequently Asked Questions
How long does a Bambu Lab hotend last?
The hotend assembly typically lasts thousands of hours. The nozzle itself (hardened steel on X1C) lasts much longer than brass nozzles on other printers.
Can I replace just the heater cartridge?
On Bambu Lab printers, the hotend is an integrated assembly. It is easier and safer to replace the entire hotend unit rather than individual components.