Fan running at full speed after shut down.

My brand new, three day old 8 core Mac Pro has already frozen three times. I have been reading about the screen garbage and then the freeze. That is happening with me, too. But what is going on right now as I type on my old G4 is that the fan on the new Mac Pro is running full speed and the computer has been shut down! The fan has been blowing like this for at least 30 minutes. I am hesitant to unplug. But I can't just leave the office with it blowing like that. What is going on?

Have a lot of USB stuff attached...
Apple keyboard/mouse, Kensington track ball, (then through hub) Logitech web-cam, External HD (USB) for time-machine, epson scanner, iPod USB cable, shuffle, dock, and...ah ha..may be a culprit...a Microsoft joystick for playing x-plane (when I was thinking about what I do when this happens, I said I'd switched resolutions to use xplane..but, of course, I would have had the joystick plugged in as well..this could be the one difference (I only connect the joystick when I'm going to use x-plane)).
I will experiment some tonight...shutting down with and without the joystick to see if that makes any difference.
Now that I think of it, that seems to be the one 'difference factor'...and it would be Karma to have the Microsoft hardware messing up my Mac.
I don't have any extra PCI...nothing in firewire.
Thanks for giving me a possible lead...I'll report back.
Message was edited by: midiotlv
Message was edited by: midiotlv

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TS1433 Fans run at full speed after computer turns on

Fans run at full speed after computer turns on, and a lot of times while i'm working they suddenly start blowing and won't stop. Tried the reset SMC, nothing happens. Also the unplug powercord-method does nothing.
Anyone?

Exactly what method did you use to reset the SMC, every Mac has different methods and I want to ensure you used the method for an Intel based Imac. The correct instructions are in the iMac SMC and PRAM reset link. Do the SMC reset at least 2X!

IMac : Fans run at full speed after computer turns on and male terrible noise

The noise is unbearable.
I have tried plugging it off/on, w the power cord, resetting SMC and NVRAM-nothing. Also, when I put it
to sleep mode, it goes quiet, but then goes back to sleep mode every 5 sec until i RESTART IT.
Current values show, left fan: 998 RPM
RIght fan: 1256 RPM
Please, help, I'm not a pro so use basic language, please.
<Edited by Host>

*MAKE, sorry

IMac fan runs full speed on shut down

Hi Everyone, this has probably been discussed before, but I may have some new information to add that could interest the tech savvy people out there.
My iMac runs perfectly fine; more or less as it did when it was new. In OS X, when I shut down the computer, the fan runs at full speed indefinitely, unless I unplug it or boot back up. When running, the fan is perfectly normal (increases speed a bit when doing something taxing). I've never heard it at full speed before until this started happening. After following the SMC reset procedure with no luck (I'd like to add that the SMC reset only says it relates to fan problems when the computer is ON), I searched a bit and noticed there are one or two cases where a problem like mine was believed to be a motherboard issue, and therefore a costly fix.
However, here's the fun part. When booted into Windows 8.1, shutting down the iMac does not cause this issue to occur. It stays silent, as it should, even if I disconnect then reconnect the power. This leads me to believe it's unlikely to be a motherboard issue. However I've wiped, restored, and reinstalled fresh copies of Mountain Lion, Mavericks, and Windows 8.1, and the result is still the same: if I don't want to have to unplug it from the wall, then I have to use Windows to shut it down.
So then, my questions are these:
-What is the difference between shutting down from OS X and shutting down from Windows?
-Is an operating system allowed/able to touch BIOS settings?
-Is it possible to still be a hardware problem, given this difference?
My default OS is OS X, and it makes no difference if I change that to Windows. I also did a PRAM reset, even though that has nothing to do with fans...
I'd certainly like to avoid a costly repair, if it's just something that a future software update will fix.
Thanks in advance!
-Jon
iMac 27", Late 2012, 3.4GHz i7, 3TB Fusion Drive, 16 GB, OS X 10.9.4

Hey, thanks for the response.
The "Startup after power failure" option was not checked.
I'll try the Extended Hardware test when I get some spare time again - probably tomorrow night. After that I suppose it is time to either take it in for service/diagnosis, or just keep using Windows to shut it down. Sleep mode is unfortunately not an option because it eventually goes into hibernate state, which has the same problem as turning off. I don't like to leave the computer on all night, just from a power-conscious point of view (but yes, I know today's iMacs use very little power). I have it on a power bar now, so I just flick the switch off when I power down. It's not bad as a temporary solution - perhaps permanent if the shop says they have to replace the motherboard.
As for contacting Apple... I had a 1-hour conversation with them about my iCloud account, because it suddenly stopped working on this Forum site (hence the new account with no points). Anytime I sign in, it forwards me to the "page not found" error page. This happens even if I sign in on the apple store then click over to here. If my login info has an open session, then Discussions just doesn't work. They were completely baffled (understandably), because the account works on iTunes, iCloud.com, Apple store, and everywhere except Discussions. I was on the phone with them for over an hour - and the kicker is, even after telling them the same thing happens in other browsers, from other computers, they actually forwarded me to the iMac team. This is when I lost faith in Apple support. When one of the staff asked why I don't just phone about the issue, instead of trying to get access to the forums just to post about it, I told them I didn't want to pay $50/hr (or whatever the insane rate is for Mac hardware issues), only to be put on hold and sent around between departments, just to be told I need to send it in for service, which I'm probably not going to do if it's the motherboard. They never did get back to me about my account issue...
Anyway, sorry for the rant, I'll keep you posted about the hardware test and more SMC resets.

Fan running at full speed and all the time!

Hi,
I was wondering what could be the reason for my fan running on full speed at all times?
It is pretty annoying especially when I am in a quiet room. This just started happening this morning and I thought it was just going to stop but it didn't so I restarted my MacBook and shut it down also and still no luck.
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I reset the PMU and the fan is still going at full blast right when the MacBook starts up.
Will I know that the PMU is reset or will it just fix the problem if it is?
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The computer is running fine but it's just the fan that is really loud and going at full speed and the battery life is extremely short for some reason.

Case Fan Running at Full Speed

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This question was solved.
View Solution.

Hello design_guy,
You should not have any problems with the fans running at full speed other than the fact you may decrease the life cycle of the fan.
You may want to install some software on the computer that will allow you to adjust the fan speed from the computer which may help you prolong the life of the fans and give you a little control over them.
Something like SpeedFan should do the trick.
If I have helped you in any way click the Kudos button to say Thanks.
The community works together, click Accept as Solution on the post that solves your issue for other members of the community to benefit from the solution.
- Friendship is magical.

Very noisy iMac, fans running at full speed even when performing smal tasks

I have a 2009 21 iMac, recently the computer became very noisy with the fans running at full speed all the time even when checking the email or just using Safari. I don't do anything crazy like 3d renderings so I don't know why the fans wont stop. I recently cleaned it but this didn't seem to solve the problem.
Anyone knows what's the problem and how can I fix it?
Thanks

Hello irisfailsafe
Welcome to Apple Discussions
Reset the SMC > http://support.apple.com/kb/HT3964
+1. Shut down the computer.+
+2. Unplug the computer's power cord.+
+3. Press and hold the power button for 5 seconds.+
+4. Release the power button.+
+5. Attach the computers power cable.+
+6. Press the power button to turn on the computer.+
Dennis

Macbook May 2010 edition exhaust fan runs at full speed

Bought a new Macbook around February 2011. Yesterday all of a sudden while watching Netflix, the exhaust fan started running at full speed (Approximately 6200 RPM). I thought the machine was overheating. So I immediately shut it down and let it cool. But I noticed the machine was barely warm.
When I started it up again, it started making the same noise with the exhaust fan running at full speed. I installed SMCFanControl and I see that the CPU is barely warm - 35-37C and yet the fan is running at full speed. I looked at the CPU/HDD usage and there is barely ANY usage (~90% idle). Nothing out of the ordinary. So it definitely doesn't seem to be a heating issue.
In order to troubleshoot this I have done the following:
1. Installed latest upgrade - Snow Leopard 10.6.7
2. Reset SMC
3. Reset the PRAM
4. Tried booting from the install DVD. There as well it exhibits the same issue.
Neither of these steps have helped me with my situation. I would really hate to go to the apple store as its always crowded and would end up wasting time. Are there any other steps I could try?
Update: I tried running the Apple Hardware Test from the DVD. This is the error code that I got: 4SNS/1/40000001: TN1D- -1.000
Can someone please tell me what this means?

I don't know what that code means for sure, but it sounds like one of the temperature sensors may have died, so the fans just run at full to cool.
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One of my MACs (G5 2.0DP) can't slow down - the fans runs at full speed all the time (OSX 10.3.9) - hardware test - PMU - disconnect powersupply - exit single user mode - I think I did all that's in the "book" - but the fans are still running at full speed - all the time.
any ideas?

Hello,
I am not sure if you have the same issue, but I might be worth it for you to read the archive:
http://discussions.apple.com/thread.jspa?threadID=561296&start=0&tstart=0
And here is the end of my story:
Regarding my issue with the fan fan full force, yes it was resolved... but not without fighting for it!
Fortunately the machine was still under warranty, and I left it with Apple care during an oversea trip in August. End of August I picked it up suppositely fixed and after a few hours of work I noticed the same symptoms were still there! You can be sure I made it clear to Apple service I was not happy. I left the machine again for a week and 1/2 and picked it up again. They told me they replace the logic board. Again a few hours of work of testing and this time I could repeatidly hang up the machine. Back to Apple, I told them I didn't want to pick it up until they REALLY tested it! This time they replace the logic borad again, the power supply and something else?...
Anyway since then the machine works just like it did before : great, no hardware system related issues.
Unfortunately I cannot tell you for sure what was the problem: logic board? CPUs? power supply?... and I could not get the information from Apple care, especially I would have been interested in the specific procedure they follow to fix my problem... but for some reasons they don't want to share this information...
I hope your machine is still under warranty... other wise you'll have to weigh the pros and cons to have it fixed, especially if they replace the logic board ($900 I believe) or any other main components...
I hope this help,
Good luck,
David
Dual 2 GHz PowerPC G5 Mac OS X (10.4.8)

My iMac G5 Fans run at full speed when using regular everyday applications.

When using just normal everyday applications such as using about 30 min of Safari to surf the web or maybe something else, my fans run at full speed. I have just got a new logic board replacing my old faulty one. How can I fix the fan problem?
Thanks!

Hi again Miriam,
With more news for you and iMacG5 on the fans go crazy. I just got back my computer from the repair center. After more than a week under observation, the technician told me that they just couldn't replicate the problem. They had the computer running non-stop during all this time, not even allowingit to go to sleeo mode and nothing.
The CPU fan never went beyond 2300 rpm (or so) and never went to sleep mode on and off by itself. Furthermore, they ran all possible tests and everything comes back as OK.
Right now I have a movie running on the background, together with a photo processing software open and other smaller processes and the CPU fan is running at 4361 rpm !!! the temp of the CPU is 66.3 Celsius.
Any thoughts??? It's really making me crazy because the computer was neverlike this and now it sounds like a hair dryer. I emphasized with them the fact that this just started after they changed the logic board and as coincidence after Ioaded the security update 2006_04. The technician told me it may be software related. If the computer doesn't go to sleep by itself, then he recommended to reload the operating system.
Any comments appreciated.
Zwirek

Fans run at full speed

As in subject, my brand new iMac Aluminium 20" 2GHz has a problem: fans run at full speed...
After reset of PRAM or SMC, fans start slowly (1200rpm) but rise ti 3500rpm after few minutes and they don't change until a new restore of SMC.
cpu 3-4%,
no apllication opened,
nothing in dashboard.
What's happen?? I've never had a problem with my mac!
PS: sorry for my bad english, I'm italian!
cerion
Message was edited by: cerion86

Hi, just an update -
I ran the Apple Hardware Test on startup, and it returned this hardware error: 4SNS/1/40000000:TpoP
I brought my machine to the Apple Store where I bought it and they ran their diagnostics and said there was nothing wrong. So when I picked it up we booted it up in the store and the fan was about 1200rpm, no problem. We ran the Apple Hardware Test in the store and it didn't give the same hardware error that I'd had before.
So, I didn't really have any ammunition to press them any further on it and for the last week it's been fine. I had the fan race on me again last night but I hope it was an isolated incident.
As for downgrading to OSX 10.4, I'd consider it but I don't feel that I should have to do that to make my hardware perform correctly.
Re. smcFanControl, I thought the purpose of that is to make the fans run faster/more often, but if anyone's used it to stop them from running too fast/too often I'd be glad to hear from you.
Maybe the 10.5.2 version of the OS will take care of this problem, if indeed a problem exists.

Fans are running at full speed after hard drive upgrade. Used same brand drive.

My Western Digital 500GB hard drive crashed. The date on it is Aug. 2010. I swapped it out for a Western Digital Caviar Black 1TB. All plugs were identical including the temp sensor cable. My fans now run at full speed. What gives? BTW. This is th 3rd WD hard drive to fail at my office in multiple iMacs. I have a 21.5 iMac i3 3.06ghz. I have tried the SMC reset,.. no luck. Reset the PRAM,.. no luck. Hard drive and computer function perfectly, it just sounds like a loud annoying PC.

After a little more research the only thing I found for 21.5" mid 2010 imac were three part numbers for three sensor cables which are a function of vendor:
922-9215, Hitachi
922-9216, Seagate
922-9622, Western Digital
The strange thing here is these are vendor specific and not model within vendor specific. So you started with a WD drive and replaced it with different model, but still a WD drive. So you would think it would require the same sensor cable.
Maybe the drives are different enough for this to matter. Or maybe you should check the connections one more time. Be it model of drive or connections, whichever it is, the sensor cable is the source of your problem.

HT3964 Fans running at full speed even after SMC reset.

I have reset the SMC twice on my iMac 24" (early 2009) and my fans still run at full speed, but only after I've been away from my computer for a while. It never happens while I'm using it. Any suggestions? My Apple Care plan ran out a few weeks ago and so I can't call in without paying.

Try iStat Pro and see what temps are being seen by the system.
http://islayer.com/apps/istatpro/
I know this won't fix it but it might allow you to see which sensor might be acting up.
Have you tried a PRAM Reset? Again just fishing.
Option + Command + R + P during powerup thru 2 chime sequences

Fan runs at full speed all the time

The fan on my brand new iMac 17" runs at full speed all the time, creating an unbearable amount of noise. The activity monitor shows 99% spare time, i.e. nothing much is running.
I updated all software, checked the firmware version (it was the latest already) and performed an SMC reset. I also unplugged it for several hours, as some people have suggested.
I downloaded smcFanControl and it says that the ODD fan is running at 5200 rpm all the time. The CPU and HDD fans seem to run at normal speeds. smcFanControl also reports a cool 39 deg.
Does anyone have any idea of what to try to fix this problem?

I don't have a solution but thought I'd add a computer that showed the same behaivor.
A 20" iMac I was configuring for my company did the same thing, but just once so far. I used it briefly just out of the box and didn't have any problems. It's a stock install of OS X 10.4.8, no other software installed. Turned it on several days later and the fans ran during the 2 hours I used it to run Safari via Airport. I turned if off after it started to smell like hot electrical components. Activity monitor looks completely normal. After shutting it off for two hours, unplugging and re-plugging AC and keyboard, it came back on with no fans. I did not do the SMC reset or any updates between the power cycle.
ps. Repairing permissions is Voodoo
http://daringfireball.net/2006/04/repairpermissionsvoodoo

Mac Fan runs at full Speed from start, even in standby mode!

Hi Folks
Since this night my iMac's fan (summer 2012 model) runs at full speed from the beginning of powering it on. It even runs at full speed when I put the iMac to sleep!
So far I tried to reset the SMC three times, noo effect at all. I checked also the activity log, no processes or other activities are causing this. I read about defect HDD sensors, could that be the problem?
Any ideas how to fix or at least control this issue???
Thank you all for your help!
Matt
PS: That's a pretty annoying sound I'm hearing here, I feel like on the roof top of the Hancock Building at wind speed 200!

I have tried the SMC reset as instructed and the fan is running normally. It is a bit of an intermittent problem so I will monitor the performance of the computer over the coming weeks. If it persists, I will take it in to a service centre while it remains under warranty.
I guess the "cure" I had stumbled across by accident was nothing to do with turning the computer upside down, it was because I was unknowingly performing an SMC reset. The reason I turned the computer upside down was to find the serial number on the base of the stand so I could report the fault to Apple. Of course, when I plugged it back in to contact the support line, it worked fine.
Once again, thanks for your help.

Fan running at full speed after shut down.

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