Bambu HMS and error codes

A Bambu printer that stops with 0700_2100_0002_0001 on the screen is telling you quite a lot: which part of the machine, which AMS, which slot, how serious. I wanted to read that without searching each time, so this takes any code apart and, for the codes I see most, says in a line or two what is wrong and what to do.

How to use it

Type or paste a code. It accepts:

an HMS code — 0700_2100_0002_0001, with dashes, spaces, HMS_ in front, or as 16 hex digits;
a print error — 0300_400C, or the decimal print_error value from the printer’s report (50348044);
a report — paste JSON from the printer’s MQTT messages (or Home Assistant’s attributes) and every "hms": [{"attr": …, "code": …}] entry and the print_error are decoded;
several codes, one per line.

Each result shows the code split into its groups — module, unit, part, severity, error number — and names them: AMS B, slot 2, filament feeding, Motion controller, nozzle heater, fatal. For about 210 common codes (heaters, fans, motors, homing and levelling, doors, the Lidar and AI detection, AMS, AMS lite and AMS HT feeding, cutter, buffer and drying, and the frequent print errors) there is a short meaning and what to do. Every code gets a link to its page on Bambu’s wiki — choose your printer, since the wiki keeps separate pages for the H2 series, P2S and A1 — and to Bambu’s HMS search.

Browse the notes lists them all with a filter; How the codes are built explains the structure.

The printer farm dashboard (3-D printer farm dashboard) decodes the HMS messages of Bambu printers on their cards with the same code, and each one links here.

How the codes are built

An HMS entry is two 32-bit numbers. Written as hex, MMUU_PP00_SSSS_EEEE:

MM the module — 03 the motion controller (the printer itself: heaters, fans, motors, sensors, doors), 05 the main board (network, storage, files, cameras), 07 AMS and AMS 2 Pro, 0C vision (Micro Lidar, cameras, AI failure detection), 12 AMS lite, 18 AMS HT;
UU the unit — which AMS, 00 = A to 07 = H;
PP the part — for the AMS, 10–13 the feed motor of slots 1–4, 20–23 filament feeding in slots 1–4, 70–73 loading and unloading, and so on;
SSSS the severity — 1 fatal, 2 serious, 3 common (a warning), 4 info;
EEEE the error number for that part.

Print errors are one number, MMUU_XEEE: the same module and unit, and a first digit that says what happened to the job — 4 stopped (or could not start), 8 paused and waiting for you, C a notice.

The module and severity values are the ones Bambu Studio and the Home Assistant Bambu integration use. The part names and the meaning of the print error’s first digit are my reading of the codes Bambu has published, so treat them as a guide.

Where the descriptions come from

The meanings and fixes are written for this page, in my own words, from Bambu’s published code list and the wiki — not copied: Bambu’s wiki text is not licensed for reuse. For the official wording, and the long troubleshooting guides with pictures, follow the wiki link on each code. The links point at the wiki page for that code where I know one exists; for other codes the link is a best guess at the page name, and the HMS search is the fallback. A note here is no substitute for Bambu’s instructions when a heater or the power supply is involved: when the code says power off, power off.

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Any current browser; it works offline once the page has loaded.

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Works with

How to use it

How the codes are built

Where the descriptions come from

Browser support

Privacy