This article describes the common AMS loading and unloading failure troubleshooting methods, when you encounter AMS loading and unloading failure, you can refer to this article for troubleshooting according to the error message and fault phenomenon. Before troubleshooting, we recommend that you first take this Wiki to learn the main functions and workflow of AMS:

AMS main functions and workflow introduction | Bambu Lab Wiki

1 Loading failure Troubleshooting

1.1 Failed to feed the filament outside the AMS

If this error occurs, the AMS internal hub hall switch does not detect the filament. If the filament is not pushed out of the PTFE tube, the loading may have failed for one of the following reasons:

1.1.1 First stage feeder abnormal

(1) Troubleshooting of feeder hall switch

If the feeder does not detect the filament after inserting the filament, the loading failure may be attributable to an abnormal feeder hall switch. The following is the status of the feeder LED status:

 AMS LED Status Troubleshooting | Bambu Lab Wiki

  • LED light is white when the filament is inserted
  • LED light is turned off when the filament is pulled out

Note: The load button on the screen will not light up when the feeder hall switch is abnormal and the filament insertion is not detected.

  • X-Series Printers
  • P-Series Printers

Troubleshooting method:

When the filament is inserted into the feeder, the feeder hall switch detects the insertion of the filament, and at the same time the feeder LED light will be on. When the filament is pulled out of the feeder, the hall switch detects the filament is pulled out and the feeder LED light will turn off. Therefore, you can determine if the feeder hall switch is functioning properly by inserting or pulling out the filament.

  • The feeder LED light is on when the filament is inserted and off when the filament is pulled out.

The feeder LED light does not light up after the filament is inserted, and the feeder hall switch is abnormal.

(2) Troubleshooting of feeder

The following picture shows the normal working condition of the feeder, when the filament is inserted into the feeder, the feeder LED white light is on and the feeder motor rotates to feed the filament into the AMS.

If when the filament is inserted into the feeder, the feeder LED white light is on to detect the filament but does not feed the filament into the AMS, please record the video of the feeder and contact the after-sales service.

1.1.2 Abnormal AMS internal filament hub

When the feeder is working properly, but when clicking “loading” or reading RFID, the filament is not pushed out of the PTFE tube on the back of the AMS. This may be a loading failure due to an AMS internal filament hub hall switch.

Troubleshooting steps:

You can refer to the following steps to check if the AMS internal filament hub hall switch is normal:

1. Remove the PTFE tube

2. Unscrew the two fixing screws on the AMS main frame

3. Turn the AMS main frame over

Note: Please flip the AMS main frame over carefully to prevent pulling the cable off!

4. Insert the filament into the AMS internal filament hub and observe whether the feeder LED light red light is on. If the red light is on, it means that the hall switch is normal (detecting the filament)

Note: When performing the testing process, it is recommended that several attempts be repeated to determine if the feed fails due to the AMS internal filament hub hall switch abnormal.

1.1.3 The filament buffer signal lost

When there is no abnormality in the feeder and the AMS internal filament hub, and the feeder motor does not respond when the loading button is clicked, this may be due to an abnormality in the buffer, please refer to this Wiki for troubleshooting:

The filament buffer signal lost, the cable or position sensor may malfunction | Bambu Lab Wiki

1.2 Failed to feed the filament into the extruder

This error occurs when the filament has already been sent out of the AMS filament hub, but the extruder hall switch does not detect the filament. The loading failure may be due to the following reasons:

1.2.1 Stuck spool or filament

When the filament is tangled or the spool is jammed, it will cause the loading failure, please check if the filament is tangled or the spool is jammed.

1.2.2 The PTFE tube connector abnormal

If the spool can rotate normally, make sure that the filament encounters resistance at the position shown in the following figure, causing the loading failure.

If the filament encounters resistance feeding to the extruder at position 1 or 2, remove the PTFE tube to see if the feed is failing due to a damaged pneumatic connector. If the pneumatic connector is damaged, it will need to be replaced.

1.2.3 Abnormal AMS internal filament hub

If the filament hub hall switch is working properly, the feed failure may be due to the following reasons:

(1) Abnormal of the AMS internal filament hub motor

When the AMS internal filament hub hall switch detects the filament, but at this time, it may not be able to push the filament out of the AMS because the filament hub motor is not rotating. If you encounter this problem, please refer to the following figure to re-plug the filament hub motor connecting cables, and if the motor is still malfunctioning, please contact our after-sales service.

Replacing the AMS internal filament hub | Bambu Lab Wiki

(3) The AMS active extrusion wheel slipping

If there is no resistance in the PTFE tube connector preventing the filament from feeding to the extruder, the filament stops on its way to the extruder. You can verify whether there is any visible wear on the backside of the filament (the side that is coiled on the spool) by pulling out the filament from the AMS and referring to the following figure. If there is wear, it is possible that the feed is failing due to the AMS active extrusion wheel slipping and thus wearing out the filament. You can refer to this Wiki to fix the problem by replacing the AMS active extrusion wheel: Replace the AMS active extrusion wheel assembly | Bambu Lab Wiki

1.2.4 Abnormal extruder

If the filament can be fed to the extruder, but still shows a failure to feed into the extruder, it is possible that the filament is not being detected due to a faulty extruder hall switch.

Extruder hall switch failure troubleshooting

  • Remove the PTFE tube from the interface on the back of the printer;
  • Manually feed the filament to the extruder;
  • Refer to the following to determine if the extruder hall switch is functioning properly:
  • For X-Series printers:

You can switch the display to the “Temperature/Axis” and watch for the green dot light up as shown below. If the green dot is on, the extruder hall switch detects the filament.

  • For P-Series printers:

You can open Bambu Studio switch the display to the “Device” and watch for the green dot to light up as shown below. If the green dot is on, the extruder Hall switch detects the filament.

According to the above method, if there is no filament in the extruder and the green dot in the figure is always on, the feed failure may be caused by the following two reasons:

  • There is a broken filament in the extruder
  • The extruder hall switch is abnormal

You can remove the extruder from the tool head first to judge whether there is broken filament in the extruder, if there is broken filament in the extruder, please refer to this Wiki to clean it:

Extruder Clog | Bambu Lab Wiki

If there are no breaks in the extruder, refer to this Wiki to check that the Hall switch magnet is not springing back properly:

HMS_0700_2000_0002_0004: The AMS slot1’s filament may be broken in the tool head | Bambu Lab Wiki

1.3 Failed to extruder filament

When AMS successfully feeds filament to the extruder and the extruder hall switch detects that filament are being fed, but reports an error “Fail to extruder filament”, it is usually because the extruder gears have not successfully bite the filament. There are several reasons for this:

1.3.1 Extruder clog

When the extruder is clogged, the new filament can not be bitten by the extruder because there is still filament clogged in the extruder, and thus an error message that the filament extrusion failed will appear. Please refer to this wiki to clean the extruder:

Extruder Clog | Bambu Lab Wiki

1.3.2 The buffer signal abnormal

When the extruder hall switch is normal, the filament is fed to the tool head, but the extruder cannot bite the filament and extrude it, and you can print with an external filament. This may be due to a feed failure caused by an abnormal buffer signal. You can refer to this Wiki for troubleshooting:

HMS_0700_4000_0002_0004: The filament buffer signal is abnormal,the spring may be stuck or the filament may be tangle | Bambu Lab Wiki

1.3.3 The speed of the AMS filament hub motor abnormal

If the feed failure is not due to the above problem, this may be due to the abnormal speed of the AMS filament hub motor causing the feed failure. Please upload the printer log and contact the after-sales service to help you solve the problem.

How to update log files to an existing ticket | Bambu Lab Wiki

How to upload the log files of P1 series | Bambu Lab Wiki

2 Unloading failure Troubleshooting

When there is an unloading failure when using AMS, first observe if the filament exits from the extruder.

2.1 Failed to pull out the filament from the extruder

This error occurs when the extruder still detects filament inside after the AMS has been unloading for a period of time. This can be due to the following reasons:

2.1.1 Extruder clog

Unloading failure when the filament can not be exited from the extruder. This may be due to a clogged extruder. Please refer to this Wiki to clean the extruder:

 Extruder Clog | Bambu Lab Wiki

2.1.2 Abnormal extruder

When the filament has been exited from the extruder and it still shows that the filament has failed to exit the extruder. Please refer to the above extruder hall switch troubleshooting method first to check whether the green dot in the extruder icon is on. If the green dot is on, the possible causes are as follows:

  • There is a broken filament in the extruder
  • The extruder hall switch is abnormal

The specific troubleshooting method is the same as above.

2.2 Failed to pull back the filament from the extruder to AMS

This error pops up when the extruder hall switch detects that the filament has exited the extruder after a period of time of unloading, but the AMS internal filament hub hall switch still detects the filament (a complete unloading process will pull back the filament inside the AMS). This can be caused by the following:

2.2.1 Spool stuck or filament tangled

When the spool is stuck or the filament is tangled, this may cause the unloading failure. We suggest that you can first check to see if the spool is stuck or the filament is tangled.

2.2.2 Excessive resistance

(1) The PTFE tube bent too much

When the PTFE tube is bent too much above the tool head, there may be too much resistance to the filament in the PTFE tube, and the filament will not be able to be pulled back as a result, leading to the unloading failure.

You can click here to download a PTFE tube bracket that can be mounted above the tool head to prevent the PTFE tube connected to the tool head from bending too much.

The PTFE tube bracket is installed as shown below:

(2) AMS internal filament hub debris accumulation

When using AMS for a longer period of time, too much filament debris builds up inside the filament hub causing too much resistance, which can lead to the unloading failure.

You can refer to this Wiki to clean the inside of the AMS internal filament hub:

Dismantling and cleaning the filaments hub | Bambu Lab Wiki

(3) Unloading failure of special filament

If there is only a special filament unloading failure, such as PLA-CF, we recommend that you print the filament on the spool support on the back of the printer.

2.2.3 Abnormal active support sleeve

If there is a noticeable noise of the feeder when using the AMS to unload, this may be due to the active support sleeve not being fully seated in the AMS main frame, so that only the yellow gear of the feeder rotates and the black active support sleeve does not rotate, thus the spool from rotating and causing the unload to fail.

The picture below shows how to snap the active support sleeve into the AMS main frame:

2.2.4 There is a broken filament inside the filament hub

If the filament has exited the feeder, but the AMS is still unloading at this point and the feeder LED light is always red (as shown in the following figure). This could be a result of a broken filament inside the AMS internal filament hub leading to the failure to unload. Please refer to this wiki to disassemble the AMS internal filament hub for cleaning:

Dismantling and cleaning the AMS filaments hub | Bambu Lab Wiki

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