Bambu Lab HMS error code 0700-4500-0002-0001 falls within the 0700-4500 AMS buffer subgroup. The AMS buffer is an inline filament accumulator that absorbs the slack between the AMS’s intermittent feeding motion and the printer’s continuous extrusion demand. This error indicates the buffer has reported a fault condition.

What the Error Means

The AMS buffer contains a tension-sensing mechanism — when the buffer runs low on accumulated filament, it signals the AMS to feed more. Suffix 0002-0001 in the 0700-4500 subgroup indicates a general buffer fault, which can include: the buffer position sensor not reading correctly, the buffer running empty faster than the AMS can refill it (indicating a slow AMS feed rate), the buffer being mechanically jammed with a filament strand, or the buffer sensor reporting an implausible state.

Step-by-Step Fix

1. Power off the printer and AMS. Open the buffer cover or access panel for your AMS model.
2. Inspect the interior of the buffer for a filament strand that has looped or knotted inside the accumulation chamber.
3. Clear any filament tangles gently with tweezers. Confirm the buffer wheel or internal guide element moves freely.
4. Inspect the buffer sensor — typically a lever or flag switch that monitors the internal filament tension. Confirm it is not stuck in one position.
5. Reinstall the buffer cover and power on. Initiate a filament load cycle and observe whether the buffer fills and empties normally.
6. If the buffer runs empty repeatedly during printing, the AMS feed rate may be insufficient for the print speed. Try reducing print speed or maximum flow rate in the slicer settings.
7. Inspect the PTFE tube connection from the AMS to the buffer entry — a partially blocked or kinked tube can starve the buffer.

Parts Required

• Replacement buffer sensor or buffer unit if mechanical failure is confirmed

Contact Bambu Lab support for buffer component availability and installation guidance if the error persists after mechanical clearing.