2019 iMac 27” fan issues

[Nome_man]

I have a base model 2019 27” iMac (A2115) upgraded to 40MB RAM, but otherwise not messed with. Lately the fan has been running loudly non-stop. I downloaded the Fanny app to check the fan speed and CPU temp, and the fan is running at like 3400RPM non-stop, but the CPU temp only ever peaks at like 51C. I have tried resetting the SMC about 100 times and it never works, so the simple solution is unfortunately off the table. Ran diagnostics and returned an error code of PPF003, which apparently means “fan test failed (low speed)”. Called Apple, and their only solution is to take it to an Apple Store. But there are two issues: (1) of course, it just went out of warranty, and (2) I live in rural Alaska and there isn’t an Apple Store closer than a two hour jet ride. Apple offers no mail-in service for desktops apparently either. I did call a certified service store and they said one of the temperature sensors may have failed. Again, bring it in. Again, same issue that I cannot.

So my questions are:

1. Has anyone else had this issue and solved it?
2. Has anyone else replaced the fan in their A2115? Do you think this might solve the issue regardless of “thermal sensors”?
3. Where are the “thermal sensors” on this model and can they even be replaced? (I’ve Googled until my eyes are crossed and found nothing...)
4. If I am going to crack this thing open anyway, what upgrades should I consider while in there? (Swap the fusion drive for SSD? Add a PCIe SSD?)

Thank you for ANY thoughts you can offer on this. Living in a remote place definitely has it’s benefits, but when it comes to dealing with Apple issues, not so much...

Nome_man

2019 iMac 27” 5K Retina (A2115)
2013 MacBook Air 11” (A1466)
Apple Watch 3
iPhone 11 Pro

 

[chscag]

Replacing the fan won't work if the temp sensor has failed. The temp sensor would have to be replaced. Have you tried the Macs Fan Control app?

Macs Fan Control - control fans on Apple computers, also on Windows via Boot Camp

Control fans on Apple computers, also on Windows via Boot Camp. Monitoring of fan speed and temperature sensors. Solve fan noise and overheating problems, iMac HDD replacement

crystalidea.com

Give the app a try. Others have used it successfully to control a runaway fan.

 

[Nome_man]

Replacing the fan won't work if the temp sensor has failed. The temp sensor would have to be replaced. Have you tried the Macs Fan Control app?

Macs Fan Control - control fans on Apple computers, also on Windows via Boot Camp

Control fans on Apple computers, also on Windows via Boot Camp. Monitoring of fan speed and temperature sensors. Solve fan noise and overheating problems, iMac HDD replacement

crystalidea.com

Give the app a try. Others have used it successfully to control a runaway fan.

Thanks. I haven’t tried the app but I will.

Does anyone know where the temp sensor on this model is? As I said, I have not been able to find anything searching myself.

 

[Nome_man]

So I have tried using the Mac Fan Control app, but either I am not using it correctly or it isn't working. As you can see in the screenshot, I have tried to set the fan to a constant rate but it is still just going maximum. Not sure what else to do here... Any help is greatly appreciated!

 

[Lankyman]

I have a base model 2019 27” iMac (A2115) upgraded to 40MB RAM, but otherwise not messed with. Lately the fan has been running loudly non-stop. I downloaded the Fanny app to check the fan speed and CPU temp, and the fan is running at like 3400RPM non-stop, but the CPU temp only ever peaks at like 51C. I have tried resetting the SMC about 100 times and it never works, so the simple solution is unfortunately off the table. Ran diagnostics and returned an error code of PPF003, which apparently means “fan test failed (low speed)”. Called Apple, and their only solution is to take it to an Apple Store. But there are two issues: (1) of course, it just went out of warranty, and (2) I live in rural Alaska and there isn’t an Apple Store closer than a two hour jet ride. Apple offers no mail-in service for desktops apparently either. I did call a certified service store and they said one of the temperature sensors may have failed. Again, bring it in. Again, same issue that I cannot.

So my questions are:

1. Has anyone else had this issue and solved it?
2. Has anyone else replaced the fan in their A2115? Do you think this might solve the issue regardless of “thermal sensors”?
3. Where are the “thermal sensors” on this model and can they even be replaced? (I’ve Googled until my eyes are crossed and found nothing...)
4. If I am going to crack this thing open anyway, what upgrades should I consider while in there? (Swap the fusion drive for SSD? Add a PCIe SSD?)

Thank you for ANY thoughts you can offer on this. Living in a remote place definitely has it’s benefits, but when it comes to dealing with Apple issues, not so much...

Nome_man

2019 iMac 27” 5K Retina (A2115)
2013 MacBook Air 11” (A1466)
Apple Watch 3
iPhone 11 Pro

Personally for something as new as this I would leave it to the professionals. Bite the bullet and get your wallet out.

 

[wilberforce]

So I have tried using the Mac Fan Control app, but either I am not using it correctly or it isn't working. As you can see in the screenshot, I have tried to set the fan to a constant rate but it is still just going maximum. Not sure what else to do here... Any help is greatly appreciated!

The fan is running at a higher speed (3620 rpm) than the maximum limit (2700 rpm), which tells me the computer has no control on the fan speed. ~3600 rpm is probably the maximum speed the fan can physically run at, but it should be electronically limited to 2700 rpm. This is analagous to a car that can physically go at 150 mph, but is electronically limited to 120 mph (as most cars nowadays have an electronic limit.)
Seems like a hardware control issue.

 

[Nome_man]

That is a good analogy. Thank you. When your say hardware control, do you mean the actual fan? Or do you mean something on MB that controls the fan? As I said, I did run diagnostics on it and returned an error of PPF003, which Apple said meant “low speed fan issue”. Is this something that just replacing the fan might solve?

 

[wilberforce]

When your say hardware control, do you mean the actual fan? Or do you mean something on MB that controls the fan? As I said, I did run diagnostics on it and returned an error of PPF003, which Apple said meant “low speed fan issue”. Is this something that just replacing the fan might solve?

I don't know; my point is that it seems like an hardware issue, not software. It could perhaps be as simple as the fan connector.
Some background info:

Computer fan control - Wikipedia

en.wikipedia.org

On some fans it will run at full speed if there is no signal on the control (PWM) pin. But I don't know for the iMac.

 

[wilberforce]

ignore, duplicate post

 

[wilberforce]

I found this on a discussion forum:
Quote:
"I experienced the same problem on a 2019 iMac Retina 27”: Fans always on at full speed, SMC and NVRAM resets didn’t fix it. Booting with D key pressed into diagnostics tool came up with the message indicating I might have a fan problem (ah really?) and error code PPF003.

Reading your description I realized the connector might be the issue. So I just took my flat hand and tapped several times on the back of the iMac. Problem solved - no more fan noise! Thanks so much, you saved me from having to send it back to an Apple Store !"

SOLVED: Apple Hardware Test - Error Code PPF003 - MacBook Air 11" Mid 2013

Well you’re fan connector was damaged by the previous owner or the person who last serviced the system. Your logic board will need repair someone with the proper skills should be able to replace it. Here’s an image on what the connector should look like Vs your connector The clamp latch is... -...

www.ifixit.com

 

[DannyCam]

Hi all, I have the exact same issue on my 2019 iMac, have also upgraded to 40GB RAM but that's the only modification. Have installed FanControl and my interface looks exactly the same with the fan maxed out at 3620 RPM (above the indicated max). There are no triggers for the fan kicking in, I could be using multiple applications like FCPX and Garageband and Lightroom all working in conjunction, with no fan activity, but then the iMac could be sitting doing nothing and suddenly the fans burst into max RPM or intermittent spooling up spooling down. Have you been able to find a solution OP?

I see the above post, and I did out of interest try some gentle tapping, but no joy!

Thanks all.

 

[Fishrrman]

Try taking the 3rd-party RAM out, and restoring to the factory-delivered configuration.
Does this change anything?

Try creating a temporary user account, with administrative privileges.
When you log into it, do the fans still run at top speed?

 

[DannyCam]

Try taking the 3rd-party RAM out, and restoring to the factory-delivered configuration.
Does this change anything?

Try creating a temporary user account, with administrative privileges.
When you log into it, do the fans still run at top speed?

Thank you for your reply!

The fan issue is intermittent and unpredictable, and isn't necessarily triggered by computing task load on the imac, so it's hard to test accurately and know what's working, but I have removed the 3rd party RAM (which for clarity is a single Timetec 32GB DDR4 266 CL19 1.2V 2Rx8 stick) and have rebooted so I will use it over the coming days and see if I get the issue again. If I do, I'm assuming it's not the RAM. Is there a particular reason the RAM may cause a fan issue?

Thank you.

 

[Rafaz]

Hello, did you find any solution for the matter? I'm having the same issue, once I turn on my mac the fan goes full blast and takes a long time to start. Once logged in, I see the Kernel_task consuming the CPU making the computer unusable!! really really slow, it doesn't happen all the time but it's getting more frequent, so far i've been able to fix with the SMC reset but sometimes takes a few tries. Has anyone experience this? thx in advance.

 

[wilberforce]

Hello, did you find any solution for the matter? I'm having the same issue, once I turn on my mac the fan goes full blast and takes a long time to start. Once logged in, I see the Kernel_task consuming the CPU making the computer unusable!! really really slow, it doesn't happen all the time but it's getting more frequent, so far i've been able to fix with the SMC reset but sometimes takes a few tries. Has anyone experience this? thx in advance.

This is a classic symptom of a faulty temperature sensor (or sensor connection). The computer thinks it is overheating, and kernel_task is a dummy process that denies CPU resources to all other applications in order to cool the system down.
Suggest attempt to diagnose if a temperature sensor is faulty, e.g. by MacsFanControl.

 

[Rafaz]

I see, let's say its indeed a faulty sensor, is it replaceable or it's onboard and need to replace the whole logic board?

 

[wilberforce]

I see, let's say its indeed a faulty sensor, is it replaceable or it's onboard and need to replace the whole logic board?

I am not an expert in this, but I imagine it depends on which sensor is faulty (if indeed that is the issue, which it may not be.) For example, it may be a faulty connection cable to LCD temp sensor. Firs step is to run a utility like MacsFanControl or istat menus to see if you can see if it is obvious there is an issue with a sensor.
Perhaps others may chime in who have actual experience with repairing this.
What Mac do you have, and has it ever been opened?

 

[The_Croupier]

I know on the 2009-2011 iMacs if the ambient temp sensor fails then the CPU fan will go full speed and the GPU will be throttled 50%, a benchmark in Geekbench 5 will show you this.

Run your Mac hard to heat it up then check Mac fans control and look at your ambient temp reading, when it was happening to my Mac the ambient temp was reading 18* C but everything else was up in the 50* range, a dead giveaway.

 

[DannyCam]

Hello, did you find any solution for the matter? I'm having the same issue, once I turn on my mac the fan goes full blast and takes a long time to start. Once logged in, I see the Kernel_task consuming the CPU making the computer unusable!! really really slow, it doesn't happen all the time but it's getting more frequent, so far i've been able to fix with the SMC reset but sometimes takes a few tries. Has anyone experience this? thx in advance.

Hi all, so I ended up sending the Imac in to Apple for inspection, they performed a full examination but reported that there was no hardware issue that they could find, and that they thought it might be a software bug. They wiped my mac and sent it back to me. When I received the computer back I turned it on and ran it for a day without restoring my backup, and there were no issues, (however this is not exactly a good test because the issue originally was intermittent and might go days or weeks with no problems, then randomly on other days the fan would take off, so one day with no issue is not really a measure of success).

I then loaded my most recent Time Machine backup onto the computer. No issues for a few days, but then after a week or so I started having some random incidents again of the fan running way over the max RPM for minutes or even hours at a time with no activity on the computer. My only theory now is that if it was indeed some sort of software issue that may have been solved when they wiped the unit, that I reintroduced that issue by doing a Time Machine backup, which would essentially just restore it to exactly the state it was in before the wipe.

So, my last grasp at an attempt to solve this will be to manually externally back up anything I need from the mac, not using Time Machine, perform another wipe myself, and then reinstall anything I need, hopefully not introducing whatever bug caused the problem initially.

Any thoughts?

 

[JonaM]

If you think it's software might be worth running something like Etrecheck to see what you've got installed and any extensions/software that might be causing problems - at the least it will give you a record of what you had installed so if you do start from blank you can reinstall one bit at a time and maybe narrow down what might be the cause

 

[Yebubbleman]

If your issue is, indeed, a faulty sensor, that requires a complete logic board replacement. I'd strongly advise not replacing it on your own unless you REALLY know what you're doing and you order the correct things necessary for replacement (such as tools and replacement adhesives to put the display back on the iMac). Certainly an Apple Authorized Service Provider will probably give you a cheaper repair bill and, unlike Apple, will allow you to buy (and have installed) upgrade SSDs, should you want to upgrade to a larger capacity SSD. The RAM on that thing is user-upgradable, and the GPU isn't upgradable. The only other thing you can upgrade on that thing is the CPU (so, if you want to go from an i5 to an i9, you can). I don't know that I'd opt to ship it to an Apple Store, but I might expend the effort to get it to your nearest AASP.

 

[Rafaz]

Thx everyone for your responses! In my case I don't thing its a software issue, I wiped clean and seems to be ok for a few days, after that start doing it again, I tried apple diagnostics and Etrecheck, both says the computer is ok! I've searched around and I see a very few ppl with same problem, hopefully apples sees it too and open a recall on it. In the meantime the only thing that works is resetting the SMC and sometimes it takes a few tries. I really wish it was just a software problem something with the OS that a simple firmware update would solve it. I live overseas and repair on this side of the world is really expensive!.

 

[Tobermann]

Hi all,

having similar problem here:
iMac 5K 27" 2019. Radeon Pro. Upgraded to 48 GB ram.
Fan (sometimes) runs at 3.700 rpm for no reason over hours. No CPU/GPU load. Temperatures below 40 °C. Fan starts and stops in no recognizable pattern. Tried the usual fan control apps, didn't help.

The problem started at about the time, when Apple introduced those M1-processors.
I had my Mac for repair in an Apple Store: Temperature sensors ok - just like everything else. They just reinstalled my machine, arranged the DIMMs in a different order and sent me home. Told me to reinstall the backup data manually rather than complete from my time machine backup, so that all libs are installed in a clean way from the web.
Result: Ran for a few days, then the same problem again (just like now...).
In the Apple store they told, that there ist no hardware problem but they expect this to be a problem with the iCloud servers and that they just hope that the problem is solved when a new major update for macOS is released...

Did anyone solve this problem yet?

My machine ist kind of unusable because it is SO loud.

Thanks, best regards!

 

[Rafaz]

Hi all,

having similar problem here:
iMac 5K 27" 2019. Radeon Pro. Upgraded to 48 GB ram.
Fan (sometimes) runs at 3.700 rpm for no reason over hours. No CPU/GPU load. Temperatures below 40 °C. Fan starts and stops in no recognizable pattern. Tried the usual fan control apps, didn't help.

The problem started at about the time, when Apple introduced those M1-processors.
I had my Mac for repair in an Apple Store: Temperature sensors ok - just like everything else. They just reinstalled my machine, arranged the DIMMs in a different order and sent me home. Told me to reinstall the backup data manually rather than complete from my time machine backup, so that all libs are installed in a clean way from the web.
Result: Ran for a few days, then the same problem again (just like now...).
In the Apple store they told, that there ist no hardware problem but they expect this to be a problem with the iCloud servers and that they just hope that the problem is solved when a new major update for macOS is released...

Did anyone solve this problem yet?

My machine ist kind of unusable because it is SO loud.

Thanks, best regards!

I have the same problem... I left at the apple store it's been 2 weeks already and they can't reproduce the problem! It's easy as use the computer and turn off, wait a few hours turn on and the problem would start.. But for some reason it won't happen in the apple store... I'll be picking it up this weekend, we'll see when I get home.

 

[Rafaz]

Now that "In the Apple store they told, that there ist no hardware problem but they expect this to be a problem with the iCloud servers and that they just hope that the problem is solved when a new major update for macOS is released..." is really new to me... I never heard that, but it would be way cheaper fix..