Aux Fan no longer starts automatically on P1P

Bambu Lab P Series Troubleshooting
1

Hello all,

I’ve recently updated to FW 1.09 on my P1P and now the aux fan no longer automatically spins up after the first layer, happens with all profiles no matter what speed or layer I set it to.

I can manually control it via Studio and on the printer controls so the fan definitely works.

Prior to this, the Aux Fan worked without issue for over a year.

Just wondering if anyone else has also encountered this?

Is there some new G-Code I have to insert?

If it matters, I also have the additional motherboard fan installed and added to my G-Code (which I deleted and re-created from a new copy from the P1P preset just in case which I installed as per the Official Wiki Guide).

Also, running Bambu Studio 2.4.0.70,

Screenshot from 2025-12-14 22-33-45
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Thanks, TS.

2

Check it’s enabled in the machine settings and look for M106 P2 after the first layer.

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If M106 P2 is not there you can add it manually in the layer change gcode.

3

Under the machine profile I don’t see that option

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And under printer parts all I have is:

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On the printer itself, all I have are the Nozzle choices and the flag for the Enclosure Kit

4

Well, I just grabbed the GCODE from the SD Card and sure enough, M106 P2 is not mentioned anywhere in the file except for the Print Start/End code

; CHANGE_LAYER
; Z_HEIGHT: 0.4
; LAYER_HEIGHT: 0.2
; WIPE_START
G1 F6300
G1 X100.05 Y151.448 E-.76
; WIPE_END
G1 E-.04 F1800
; layer num/total_layer_count: 2/10
; update layer progress
M73 L2
M991 S0 P1 ;notify layer change
M106 S188.7
; open powerlost recovery
M1003 S1
M204 S10000
G17
G3 Z.6 I1.217 J0 P1  F30000
;========Date 20250206========

It’s run at the start:

;=============turn on fans to prevent PLA jamming=================    
    M106 P3 S180
    ;Prevent PLA from jamming
M106 P2 S100 ; turn on big fan ,to cool down toolhead

and then just before the load line:


;========turn off light and wait extrude temperature =============
M1002 gcode_claim_action : 0
M106 S0 ; turn off fan
M106 P2 S0 ; turn off big fan
M106 P3 S0 ; turn off chamber fan

And that’s the only actual executions of that command.

5

OK, I think something is broken in BLStudio because if I set my printer as a P1S

It correctly inserts the M106 P2 XXX code.

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If I select the stock P1P profile:

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The command is never generated, I assume they broke the profile then.

Even turning on the Air filtration enhancement doesn’t change anything

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I guess technically there’s nothing stopping me from setting my printer as a P1S right?

They have the same functionality and my printer is fully enclosed, so they should behave the same way.

6

Raised a ticket on GitHub for it: M106 P2 code is not emitted for P1P printers · Issue #9124 · bambulab/BambuStudio · GitHub

7

Looks like they broke it somewhere between 2.2 and 2.4.

Since it’s enclosed it’s better to use the P1S profile anyways since the P1P profile has some differences that account for the lack of enclosure.

1 Like
8

Can this issue produce an abnormal fan speed error or a refusal to calibrate on a P1S? I’ve been fighting that issue for weeks now. BBL has sent almost an entire toolhead piecemeal and all of the parts are now replaced and it still doesn’t work.