Printer Not Detecting AMS 2 Pro or Drying Greyed Out? Cable & Firmware Checklist
If your Bambu Lab printer does not detect the AMS 2 Pro or the drying menu is missing, check three things from Bambu’s wiki: (1) update the printer firmware to the minimum supported version, (2) verify you used the new 6-pin bus cable (2.5 mm step height) rather than an old 1st-gen AMS cable, and (3) if the drying power icon is greyed out on an X1/P1 (or multi-AMS setup), connect the official 24V 4A Switching Adapter until the icon turns green. Last checked October 25, 2026.
When setting up an AMS 2 Pro for the first time, two issues come up repeatedly: either the AMS icon never appears in the top right corner of the printer screen, or the Drying function refuses to start with a greyed-out power icon. Here is the exact diagnostic checklist from Bambu Lab’s wiki as of October 25, 2026.
Symptom-by-symptom diagnostic table
| Symptom on Printer Screen | Root Cause (Per Bambu’s Wiki) | Official Fix |
|---|---|---|
| No AMS symbol in upper right of home screen | 4-pin or 6-pin bus cable not fully seated, wrong port used on P2S buffer, or outdated printer firmware. | Update firmware first; check the L-shaped 4-pin locking tab on the printer and reseat the 6-pin cable[cite: 8]. On P2S, do not plug the AMS into the spare accessory 6-pin port. |
| Unstable connection / All 4 slot LEDs flashing red | Communication fault—often caused by reusing a 1st-gen AMS 6-pin cable (1.1 mm step height). | Replace the cable with the new-version 6-pin cable (2.5 mm step height) included in the AMS 2 Pro box[cite: 4]. |
| Drying option missing on X1 or P1 series | Printer is running firmware older than late April 2025. | Update X1/P1 firmware to the latest version to unlock AMS 2 Pro drying control[cite: 7]. |
| Power icon in lower-right of Drying screen is GREY | AMS 2 Pro is not receiving external 24V 4A power (mandatory on X1/P1; limits H2/P2S to 1 drying unit). | Plug the official 24V 4A Switching Adapter into the back of the AMS 2 Pro and a wall outlet; the icon will turn green[cite: 7]. |
| Notification: “Filament in AMS outlet” when starting dryer | Filament is currently pre-loaded into the feeder or outlet tube during a standard drying attempt. | Unload the filament from the feeder, rest the spool inside the slot, close the top cover, and restart drying. |
| H2D does not know which nozzle the AMS feeds | First-time dual-extruder pairing has not been run. | Go to Filament -> AMS Setup -> Auto Mode on the H2D screen with a spool inserted in any slot and no broken filament in the buffer. |
Minimum firmware versions for drying while printing
According to Bambu Lab’s AMS 2 Pro and AMS HT FAQ, initiating a print while drying is in progress requires both a connected AMS 2 Pro Switching Adapter (on models like the P2S) and at least these firmware versions:
- H2D:
v01.03.00.00and above - H2S:
v01.02.00.00and above - P2S:
v01.02.00.00and above - X2D:
v01.01.00.00and above - A2L:
v01.01.00.00and above
If you also want the 5 posts from Cluster A (Posts #1–#5) or the interactive HTML/JS calculators for Step 4 (“Tool Front + Content Back”), let me know which one to generate next!