Prusa error 13115 (Filament Sensors Disabled) appears on the MK4 and its equivalents are #31115 on the CORE One, #35115 on the CORE One L, #17115 on the XL, #26115 on the MK4S, #27115 on the MK3.9S, #21115 on the MK3.9, #28115 on the MK3.5S, #23115 on the MK3.5, and #12115 on the MINI. This is a warning notification rather than a critical fault — the filament runout sensor has been turned off in the printer’s settings menu, and the printer will not detect when filament runs out during a print.

What the Error Means

The filament sensor monitors filament presence in the extruder feed path and pauses the print when filament runs out, giving you time to reload and resume. When the sensor is disabled, the printer cannot detect runout — if you run out of filament during a print, the printer will continue moving and heating as though nothing happened, resulting in a failed print with the nozzle dragging across empty air. This setting is usually disabled intentionally to work around a stuck or faulty sensor (see error 13113), but is sometimes accidentally turned off in the settings menu.

Step-by-Step Fix

1. Re-enable the filament sensor from the LCD menu. Navigate to LCD Menu → Settings → Filament Sensor and toggle the sensor back on. The warning notification should clear immediately.
2. Confirm filament is loaded through the sensor before starting a print. After re-enabling the sensor, load filament and verify that the printer reports the sensor as active and detecting filament — not immediately triggering a runout warning.
3. Resolve any underlying sensor issue before re-enabling. If you disabled the sensor to work around a stuck-sensor error (13113), fix the sensor issue first. Re-enabling a sensor that is still malfunctioning will interrupt prints with false runout alerts.
4. Note that this is a warning, not a blocking error. Printing can continue with the sensor disabled — the notification is advisory. However, running without runout protection is not recommended for long prints.

Parts Required

• No replacement parts are required for this fix — this is a settings change only

If the sensor re-enables correctly but immediately triggers runout false alarms or gets stuck again, contact Prusa Support at help.prusa3d.com to address the underlying sensor hardware issue.

Frequently asked questions

What does Prusa 13115 mean?

Prusa error 13115 (Filament Sensors Disabled) appears on the MK4 and its equivalents are #31115 on the CORE One, #35115 on the CORE One L, #17115 on the XL, #26115 on the MK4S, #27115 on the MK3.9S, #21115 on the MK3.9, #28115 on the MK3.5S, #23115 on the MK3.5, and #12115 on the MINI. This is a warning notification rather than a critical fault — the filament runout sensor has been turned off in the printer's settings menu, and the printer will not detect when filament runs out during a print.

How do I fix Prusa 13115?

Prusa error 13115 means the filament runout sensor has been manually disabled. Learn how to re-enable the sensor and protect prints from filament runout failures.