Fan-Test failed, but all fans physically work and software pointing to random-ish failed fan(s). - Hardware, firmware and software help

RE:

Peterhd — Fri, 24 Apr 2026 14:48:33 +0000

Posted by: @hemo

Hi, I can get the fans to pass the test if i remove the shroud. Do you put the shroud back on after the pass test ?

Yes, the shroud is important to directing the cooling air in the right direction. I've been doing this when needed for a while. It is a pain.

I did update the firmware to a recent beta which helped with passing the test with the standard shrouds on, at the recommendation of prusa support.

I'm getting errors during print now that the fans aren't working, when visually, verifiably they are. So I disabled the check.

RE: Fan-Test failed, but all fans physically work and software pointing to random-ish failed fan(s).

Hemo — Tue, 21 Apr 2026 05:44:56 +0000

Hi, I can get the fans to pass the test if i remove the shroud. Do you put the shroud back on after the pass test ?

RE: Fan-Test failed, but all fans physically work and software pointing to random-ish failed fan(s).

ljvollme — Thu, 26 Mar 2026 18:46:56 +0000

3 Things I did to get my 5T XL to pass all fans after upgrading from 2-5T:

1) Set the fan type for newer (2026 for me) print heads if they have the silver print fan. This is in settings>system>tools>print fan type

2) remove all tools' print fan shrouds

This had my 3 new tools passing about 50% of the time but never all together. the trick that got it all to pass for me that I haven't seen on any forums/reddit was:

3) up end a can of compressed air (so you shoot out some liquid co2) and blast the center of the fan where the bearing is to flash cool it, decreasing bearing resistance temporarily. all fans passed immediately after doing this.

Would be really great if Prusa could back off the sensitivity on these fan tests, I've assembled 3 XLs, single tool, dual and 5T, every single one had functional fans, every single one initially failed the test, every single one had to be bypassed by some amount of disassembly, brute force test running and air cannister use.

RE:

TRailfan2 — Sat, 31 Jan 2026 20:43:47 +0000

Hey folks, another XL newbie here with the Print Fan fail error message after assembly of a new XL. Updated firmware. This error was driving me crazy. All of the fans were clearly running fine, and I could not find any pinched cables. I tried all of the suggestions online. 1) removing the fan shroud - didn't work. 2) loosening fan screws - didn't work, 3) changing fan setting under Tools from black to silver - this was my first sign of hope, SOME of the fans then passed switched to silver AND removing shrouds. But, I could never get them all to pass at the same time and different ones failed randomly after each fan test. 4) I tried putting my finger on the fans just a bit to slow them down, that didn't seem to help. Finally, I found a solution - 5) I put a piece of painters tape over each fan outlet - without the shroud. Note that I did not have the tape on during the high fan test, only for the slow speed test (I had to put in on quickly). Amazingly, this solved it for all fans at the same time! So, I needed to remove shrouds, set fans to silver (mine were), and use tape over the outlet. I hope this helps someone else! Prusa really needs to fix the fan tolerance settings.

RE: Fan-Test failed, but all fans physically work and software pointing to random-ish failed fan(s).

Bearded Printer — Fri, 02 Jan 2026 04:35:50 +0000

Thank you! This saved me!

When I got my 2T XL set up, all I had to do was remove the fan shrouds for them to pass, but after upgrading to the 5T, suddenly the hotend fan test failed on 1, 2, and 3. I barely kept my finger in the middle of the hotend fans during their tests to hold them back just a tad and they passed!

You're a winner!

RE: Fan-Test failed, but all fans physically work and software pointing to random-ish failed fan(s).

Hammbone — Tue, 02 Dec 2025 05:47:44 +0000

Removing the print fan shrouds fixed my print fan calibration failures.

RE: Fan-Test failed, but all fans physically work and software pointing to random-ish failed fan(s).

PSommerer — Thu, 20 Nov 2025 22:03:21 +0000

I had the same issue with #1, 2 and 3

Its an RPM issue. I hit it with some compressed air to overspeed it just a tad, based on what I read here, and it still failed.
But I did the same thing to slow it down a hair and it passed... So I held them back a bit by touching them slightly to slow them down, all fans passed.

So apparently the controller is expecting 1,000 - 2,000 and the fans are coming in at 2,011 or whatnot. Im guessing with the fan shroud removed it sheds a bit of backpressure and reduces the rpms enough to matter.

Prusa admins should take a note and add a higher margin of error on the calibration.

RE: Fan-Test failed, but all fans physically work and software pointing to random-ish failed fan(s).

Fuzzybits — Thu, 05 Jun 2025 16:57:14 +0000

Thanks for mentioning - this did it for me, changing from the "black" fan to the "silver" fan in the settings.

RE: Fan-Test failed, but all fans physically work and software pointing to random-ish failed fan(s).

Renfa — Fri, 25 Apr 2025 02:59:26 +0000

This has probably been solved but after mine failed the other day, I went to tool settings after the failure and there was a setting to change from black fan to silver (which mine has) and this fixed the issue for me.

RE: Fan-Test failed, but all fans physically work and software pointing to random-ish failed fan(s).

AndiY82 — Mon, 19 Aug 2024 09:18:29 +0000

Same issue With one of the Fans on my XL since yesterday.
Fans move free and I couldn’t find any dirt or something that could cause the problem.
then I took each tool and checked rpm at 100%. The fan which fails the test has higher rpm than the one which passes the test. 🤷