MacBook Pro fans spinning at high speed when CPU idle

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Level 1

4 points

MacBook Pro fans spinning at high speed when CPU idle

A few days ago the fans of my MacBook Pro with the M1 CPU (MacBookPro18,1) started spinning loudly. Left one is running at 4300 rpm and right one at 4700 while the CPU is 97% idle and the temperature is at around 40 C. I don't see any reason for the fans to be spinning so fast. What could be causing this when the temperature is low?

I've tried upgrading to the latest version of the OS that's currently available (Sonoma 14.5), but the problem persists.

I've tried starting in safe mode, but the problem persists. It even occurs in the boot selection screen. The fans only stop spinning when the computer is off.

I'm trying to think what may have triggered this, and the only thing I can think of is that may be related to evaluating the game porting toolkit: Game Porting Toolkit 2 - Games - Apple Developer

The Macs Fan Control app shows that both fans are on auto, so it appears the default auto mode is not acting the way it should:

Setting the fan speed according to sensor values seems to fix the problem, but that only works while the app is running. They continue spinning after it's closed. Does anybody have any recommendations to fix this problem?

MacBook Pro 15″

Posted on Jun 28, 2024 10:32 PM

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Answer 1

Jun 29, 2024 9:13 PM in response to icastano

I haven't really monitored the system temps & fan behavior of the M-series Macs yet. I haven't really encountered any issues with them which has required me to pursue such monitoring.

In general I have observed that it can take these Apple laptops a while to have the fan speed diminish even once the system temps have recovered.

Try running the Apple Diagnostics to see if any hardware issues are detected.

Run the third party app EtreCheck and post the complete report here so we can examine it for possible clues.

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Answer 2

Jul 11, 2024 6:36 AM in response to icastano

icastano wrote:

Took it to an Authorized Service Provider who confirmed the issue, but did not found any explanation either. He suggested reinstalling macOS, which I haven't done yet...

That is why I suggested posting the complete EtreCheck report here so we can examine it for clues since most of these situations usually involve issues with third party software. It is easier to uninstall the troublesome software than it is to perform a clean install of macOS since you will most likely bring the problem back as soon as you restore from a backup.

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Answer 3

icastano Author

Level 1

4 points

Jul 10, 2024 10:47 PM in response to HWTech

Apple Diagnostics did not detect any issues, neither did EtreCheck. I tried upgrading to Sonoma 14.6 beta, but the problem persists.

The fans continue running at max speed constantly, despite the CPU being idle and the temperature monitors are around 40 C, which should not cause them to run so fast.

In addition to that the screen sometimes turns off unexpectedly, comes back on after a key press, but turns back off again in a couple seconds. This often results in a crash after a while.

Took it to an Authorized Service Provider who confirmed the issue, but did not found any explanation either. He suggested reinstalling macOS, which I haven't done yet...

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MacBook Pro fans spinning at high speed when CPU idle

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