Selftest (MK2/S)

Updated 8 months ago ​by Tomáš Chvalina

The first thing you need to do after assembling your printer is running the Selftest procedure. This routine checks for the most common issues in the build quality and electronics wiring. The Selftest prompt appears automatically on the screen once you turn on the printer for the first time. To start the Wizard, select [yes] by pressing the knob. You can manually start the Wizard at any time from LCD Menu - Calibration - Wizard.

This procedure should not be necessary for pre-assembled printers.
After the initial calibration, the Selftest can be found in LCD Menu -> Calibration -> Selftest

The Self-test procedure checks the following:

  1. Extruder and print fan functionality
  2. Heatbed and hotend wiring
  3. XYZ motors wiring and functionality
  4. XYZ endstop mechanical settings and wiring axis length
  5. Loose belt pulley test

Both progress and result of each step are displayed on the LCD screen. If the self-test process runs into an issue, the LCD screen will display a corresponding error message. All errors are described below.

Self-test error messages (MK2/S)

Extruder & Print fan test

Front print fan/ Left hotend fan - Not spinning:

  1. Make sure that both of your fans are correctly connected as described in the MK2/MK2S Electronics Wiring.
  2. Check for any blockage that could prevent either of the fans from spinning. 
  3. Go over the wiring and make sure that none of the zip-ties is over-tightened, which prevents the fans from spinning.

Heatbed & Hotend test

Please check/ Not connected - Heater/ Thermistor: Bed/ Heater - Wiring error:

  1. Make sure that both thermistors and heater are connected properly according to the MK2/MK2S Electronics Wiring guide.
  2. Check if your heated bed cables are not damaged by an overtightened zip-tie. 
  3. Investigate your Heated bed thermistor. It must be perfectly attached underneath the Golden Kapton tape.

XYZ endstop & motor test

Endstops - Wiring error - {XYZ}:
Motor - {XYZ} - Endstop {XYZ}: 

  1. Once this error is triggered, it means that either X/Y endstops or X/Y motors were not properly plugged in the miniRAMBo board. 
  2. Simply check the MK2/MK2S Electronics Wiring guide and move them to their proper position.
Be aware that if both endstops are incorrectly mounted, Selftest will not be able to recognize the mistake. If you need to re-assemble the wiring, be extra careful.

Loose belt pulley test

Loose pulley - {XY}:

  1. Make sure that both pulleys are properly tightened. If any of them is loose, then the motor's shaft won't be able to move the axis.
  2. Make sure that your belt isn't extremely loose, as it might be just going around the pulley without actually moving either of the axes.


Find out more troubleshooting tips here: Community Forum | Assembly Manuals | Youtube channel |

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