False Filament Detection

In the event that the filament detection sensors are incorrectly reading that the extruders are out of filament, there are a few things that might be causing it.

The first and most likely option is that you have the printer auto-configured for "Both Extruders" in the Simplify3D process settings, and the printer may only have one side of filament loaded. This will leave one of the filament detection sensors open which will prevent the printer from starting. To fix this, you may either

  1. Insert a small length of filament in the side that does not have filament in order to depress the filament detection sensor
  2. Change the "Auto-configure Extruders" in the Simplify3D process settings to be just Left or Right (depending on which side you have loaded filament) and then reslice the print and use the new gcode.

Alternatively, it could be that the filament detection wires are not properly connected underneath the covers on the back of the machine​. Please remove the covers by pressing on the tabs in the areas pointed out below. Then analyze the wire connection to the limit switch to make sure they are connected securely.


Another issue may be that the limit switch is not making complete contact with the bearing that presses against the filament, causing the limit switch to occasionally disengage and read as "open". Loose wiring connections in the circuit may be at fault as well, so here are a couple of troubleshooting steps to follow:

  1. Please make sure that the limit switch is fully triggered when the filament is inserted -- you should hear an audible click from the limit switch. If the switch is not close enough to the filament channel or there is debris blocking the path, the ball bearing does not fully close the limit switch. Proper limit switch activation is shown below.



    1. If the limit switch is not triggered by the filament, use compressed air to carefully blow out any debris, and unscrew the limit switch and move it closer to the filament to make sure the switch gets fully depressed. If the bearing is still not moving properly, you will need to replace the unit or remove material from the bearing slot to allow it to move properly. You can watch this video for more instruction on adjusting the limit switch:\

  1. Insert filament into both of the filament detectors, then connect the Gigabot to a computer and open Simplify3D
    1. In the "Communication" tab of the "Machine Control Panel", enter M119 to check the status of the switches as shown below:
      1. Ensure that the filament detection units read "Triggered"
    2. If the filament detection shows that it is not triggered, then please go to step 3. If it does work, then please follow the steps below:
      1. Power cycle (turn off and turn on) the machine
      2. Start a print, then enter M600 into the command line to trigger filament detection. Did this work? Please note that it will take about 20 moves of the printer for it to trigger. If it does not work, then please go on to the next step.
      3. Heat up one of the hot ends to 200C, then in the Viki go to "Prepare > “Change filament” routine. Go through that process, start a print and trigger filament detection by removing one of the wires on the limit switch to see if it is successfully triggered. It will take about 20 moves of the printer before the filament detection triggers. Did this work? If not, then continue on to the next step.
    3. If the filament detection is not triggered, then either the limit switch, the limit switch wire, the control board, or the firmware is malfunctioning. Please follow the next steps to check the electronics.
      1. To test if the limit switch is working, use a multimeter to test continuity with the limit switch closed (lever depressed) by touching a prob to each terminal. If it is not continuous, then the limit switch is broken
      2. To test if the wire is not working, use a multimeter to test that both the red wire and the black wire are continuous. Next, check that the red and black wires on each end of the wire are NOT continuous. If either of those tests fails, then there is a break or crossover in the wire and it will need to be replaced.
      3. To test if the pins of the Azteeg are not working (see photos below and wiring diagram attachment), use a jumper wire (or just something metal) to connect the red and black pins. Then test filament detection by entering M119 into the command line or by starting a print.
        • For an Azteeg X3 Pro:​ (NOTE: The black wires share a pin)
        • Here is a screenshot of the wiring diagram. The components and pins in question are surrounded by a pink box:



If you have questions or concerns, please reach out to our support team at to work with us on resolving the issue.

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