Which Official Prusa Error-Code Index Should You Use?

Direct answer: use the official Prusa error-message index for your exact printer model, not the closest-looking model name. A CORE One L owner should use the CORE One L directory; an MK4S owner should use the MK4S directory; an XL owner should use the XL directory. Then open the Prusa article linked for the complete error code and confirm that its model and hardware scope still match your machine before changing anything.

This page is a route selector, not a repair manual. It helps decide whether you have a code lookup, a symptom without a code, or a condition that should stop operation immediately. Prusa's current article for the exact code remains the authority for explanation, procedure, parts, firmware scope and safety guidance.

Choose the Prusa error-code index for your model

If your printer is not in that table, start at the Prusa Knowledge Base product selector. Do not infer that an MK4 route applies to a MINI, MK3.5, older MK3-family machine or another variant merely because a phrase or number looks familiar.

The five-step lookup that avoids the wrong procedure

1. Preserve the complete message. Photograph or write down the full code, words on the screen and any QR destination before clearing or restarting. A partial number can point to the wrong family.
2. Confirm the exact model. Read the machine's model label and distinguish CORE One from CORE One L, MK4 from MK4S, and MK3.9 from MK3.9S. For an XL, also note which tool or dock was active when the fault appeared.
3. Open the matching model index above. The model-specific directory is the entry point. Do not stop at a search snippet or a forum paraphrase.
4. Match the entire error entry. Open Prusa's linked article and verify the complete code, named component, printer scope and any firmware or hardware qualification before acting.
5. Follow that official article or escalate. If the machine, revision, symptoms or physical condition do not match, stop guessing and use Prusa's current support route with the photos and context you collected.

Error code, ordinary print symptom, or immediate stop?

Use the model index when the printer presents a defined error message, QR route or fault code. The index is built to move from that identifier to a model-scoped article. It is not the best first tool for every poor print.

• Visible code or error message: record it, choose the exact model directory and use the linked official article.
• No code, but a print-quality problem: treat it as symptom diagnosis. Wet filament, poor adhesion, under-extrusion, a clogged nozzle or an unsuitable profile can produce a failed print without creating a matching system code.
• Smoke, a burning smell, sparking, melted or exposed wiring, uncontrolled heating, or unsafe motion: stop the machine and disconnect power when it is safe to do so. Do not keep cycling the machine to obtain a code, and do not bypass a sensor or safety check.

A code appearing during a failed print does not prove the printed part, filament or slicer setting caused it. Conversely, a weak or ugly part does not prove an electronics fault. Keep those two diagnostic lanes separate until Prusa's model-specific guidance connects them.

Why neighboring Prusa models should not share a guessed fix

Prusa publishes separate error-message directories for the models above. That separation is the useful fact: a familiar enclosure, Nextruder name or code fragment is not enough to merge procedures across variants. Hardware revisions, sensors, connectors, toolhead count, firmware and physical access can change what a code means or how a check should be performed.

The same rule matters inside the MK4 family. MK4S and MK4 have separate official routes, as do MK3.9S and MK3.9. CORE One L and CORE One also have separate directories. Pick the name that is actually on the machine, even when a search engine offers a neighboring model first.

What to collect before contacting Prusa support

• the exact printer model and, when relevant, tool number or dock;
• the complete error code and message, including a photo of the display;
• the firmware version and whether the fault began after an update;
• what operation was running: boot, calibration, heating, homing, loading, printing or tool change;
• recent maintenance, transport, wiring work, upgrades or third-party modifications;
• whether the code repeats from a cold start and whether any heat, smell, noise or visible damage is present.

That context helps support distinguish a repeatable component fault from a one-time interruption without pretending that a web page has inspected the machine. Do not remove covers, probe live circuits or continue heating solely to make the error repeat unless the current official procedure explicitly calls for that action and you can perform it safely.

Ownership decision when downtime keeps repeating

An isolated, documented code with a clear official resolution is a support event. Repeated downtime that interrupts paid work is an ownership decision: compare the time to diagnose, parts availability, spare-machine coverage and the cost of delayed output. The relevant GoodPrints ownership routes are the Prusa CORE One review, CORE One L material-capability guide, Prusa XL review, Prusa MK4S review, and the CORE One vs XL buyer comparison.

If a machine outage threatens a production deadline, a natural alternative is to move the job rather than improvise a repair. The JC Print Farm production route can cover qualified repeat work while the printer is diagnosed; it is not a substitute for repairing an unsafe machine.

Bottom line

Model first, full code second, official procedure third. Use the exact Prusa directory in the table, confirm the linked article applies to the same model and condition, and stop when the physical evidence does not match. If there is no defined code, move to symptom diagnosis. If there is heat, electrical damage or uncontrolled motion, move to a safe shutdown and official support rather than continuing a lookup.

Official sources checked

• Prusa CORE One L Print Error Messages - official model-specific Prusa Knowledge Base directory.
• Prusa CORE One Print Error Messages - official model-specific Prusa Knowledge Base directory.
• Original Prusa MK4S Print Error Messages - official model-specific Prusa Knowledge Base directory.
• Original Prusa MK4 Print Error Messages - official model-specific Prusa Knowledge Base directory.
• Original Prusa MK3.9S Print Error Messages - official model-specific Prusa Knowledge Base directory.
• Original Prusa MK3.9 Print Error Messages - official model-specific Prusa Knowledge Base directory.
• Original Prusa XL Print Error Messages - official model-specific Prusa Knowledge Base directory.