Recently I've noticed that the fan on my mid-2009 MacBook Pro has been spinning up to over 5000 rpm for no apparent reason. When this happens I'm not running any cpu intensive apps or doing anything that is taxing the system.

Even simple things like scrolling in Safari is causing the fan to go into overdrive. I've attached a screenshot where you can see that the actual temp and load of the cpu is low but the fan is spinning at over 5000 rpm.

Any thoughts as to why this is happening? I don't recall installing any new software recently that might be causing this. I'm running 10.7.4

Any tasks going wild under Activity Monitor?

Also - reset SMC and re-test.

Nothing showing under activity monitor. Tried the smc reset but it didn't help. Seems that for some reason my CPU is getting hot but nothing is being run at the time. Also there is lots of cooling under the laptop.

Maybe try shutting down your MB, wait 20-30 seconds and then boot using the Safe Boot Mode option and see if the fans behave normally.

Is the MB hot in any areas when touched and felt with your hands?

Maybe a rouge out of control daemon running when booted normally and the fans going full speed?

I tried booting into safe mode and reinstalling the OS but nothing seems to fix this problem. It seems that any activity on my Mac, such as scrolling sends the CPU temp shooting up over 90 and then the fans kick in. The strange thing is the actual load on the cpu isn't very high.

Hmmm... try the doing the SMC reset and a PRAM reset once again.

And are you saying that the fans still go crazy when booted into safe boot mode?

If so, try downloading the Mac 10.7.4 combo update, repair all permissions and dick repair with Disk Utility, shut down and boot up into safe boot mode and run the 10.7.4 combo update.

Do NOT run or have ANY other apps running while doing so.

I tried putting it into safe mode and repaired permissions and while in safe mode I couldn't get the fan to spin up at all. I tried playing a full screen movie and you can see in the photo that it taxed the cpu to almost full but the temp and fan stayed low. However when I rebooted back into normal mode the fan immediately started spinning up.

are you sure activity monitor is set to "all processes" and not "my processes"?

are you sure you are organizing activity monitor the right way (CPU tab should be blue, arrow should be pointing down)

Yes. I've double checked activity monitor and nothing out of the ordinary is running. It seems like any activity on my Mac will cause the temperature to rise and the fan to kick in, even in the load no the cpu is low.

Well that provers that you've got some third-party software causing the fan problem, as SBMode won't them. Now to find out what software is the cause.

Are you using any SMC Fan Control software that may be set incorrectly?

Try taking a shot of the open Activity Monitor window, then shut down and boot up using SBMode and do the same thing and see what extra in showing in the "normal" boot window.

If an some added process shows with a normal boot and its name doesn't make much sense, select its name -> click the blue "i" Inspect icon -> click the Open Files and Ports tab and the info should give you an idea where the process is coming from.

It can't be any 3rd party software because I erased the drive and did a complete reinstall of Lion and on a fresh copy with nothing installed it still happens. I've gone back to Snow Leopard for now and everything seems to be normal so it's definitely something screwy with Lion.

But what is strange though is that this started just suddenly a few days ago and in that time I hadn't installed anything on my computer. It seems that just suddenly Lion started messing with my system and even a fresh install doesn't fix it.

Personally I hate Lion and would rather use Snow Leopard but I like to use iCloud to sync the calendars on my Mac, iPhone and iPad so that's why I'm stuck using Lion.

I can't imagine why all of a sudden my machine is acting so strange though.

OK, so it must be something goofy with something that doesn't get loaded with a Safe Boot.

Mac OS X: What is Safe Boot, Safe Mode? (http://support.apple.com/kb/HT1564)

Did you try downloading the Mac 10.4.7 COMBO update and run it in Safe Boot?

I assume all or any MBPro firmware updates have been done and completed?

which speed/size etc 2009 macbook pro do you have?

Thanks for everyone's help on this. Yes everything is up to date with the software. My MacBook Pro is the 2.53GHz C2D 4GB RAM NVIDIA GeForce 9400M 256 MB

Is this a hardware problem? My unit is the model with only 1 internal fan, so maybe it's not spinning enough to cool the insides?

Still can't understand why though my cpu temp shoots up when I'm not putting any load on it.

There could be an internal temp sensor failure that would cause this - wouldn't be the first time. You'd need to run the Apple Hardware Test or ASD to find out, however.

I ran the AHT and it came up with this error code:

4SNS/1/40000000: TCOD - 111.125

CNET has a breakdown of the error codes and according to that list mine is the temperature sensor on the cpu. This would make sense as the cpu seems to get hot for no reason at all.

Does anyone have an idea on what it could cost to repair? Does the whole logic board need to be replaced? I'd really hate to spend any money on this computer now as I'm waiting to replace it when ever Apple releases the new iMacs.

Also is it dangerous to use it? I use my Mac for work everyday doing video and audio editing so it's pretty cpu intensive.

It could be the thermal paste on the CPU has dried out and a reapplication will resolve the issue.

That code is definitely for the CPU thermal sensor, and God Forbid not part of the logic board circuitry. And everything else was pretty well ruled out as the cause.

http://www.fountaingreen.com/fgg/pdf/apple/imac/service/FGG_AHT_ErrCodes.pdfv

How to invoke and interpret the Apple hardware tests | MacFixIt - CNET Reviews (http://reviews.cnet.com/8301-13727_7-57352461-263/how-to-invoke-and-interpret-the-apple-hardware-tests/)

But it seems odd that the fans behaved properly when in Safe Boot Mode.

I don't suppose any of the "fan Control" software could be used to control the fans, and probably not worth trying.

BTW: where on earth IS the CPU temp sensor located on that MBPro model??

BTW: where on earth IS the CPU temp sensor located on that MBPro model??

It's on the heat sink.

Any ideas on what it will cost to replace the cpu sensor?

Any ideas on what it will cost to replace the cpu sensor?

~$60+labour (1 hour). If you are going to have it opened up, have the thermal paste checked first, if it's dried up it could be causing the CPU to overheat (see it at least once a month); all it would take is cleaning and re-applying the thermal paste and it would be labour only, no parts (unless you are charged for 1/3 a shot of thermal paste).

Took my Mac to the apple store today. Very cool how the Apple Store app checks you in and tells you how long you have to wait. The genius hooked my Mac up to some apple online diagnostic thing and of course everything reported working fine, but I showed her that it wasn't fine by scrolling my Facebook wall and she could see the CPU temp shoot up to close to 90. So they are going to keep for a few days to run some extra tests on it.

Maybe they should have just used your AHT disk for a diagnosis ;)


I ran the AHT and it came up with this error code:

4SNS/1/40000000: TCOD - 111.125

CNET has a breakdown of the error codes and according to that list mine is the temperature sensor on the cpu. This would make sense as the cpu seems to get hot for no reason at all. ... ... ...

Got the call from Apple today. Temp sensor is borked so whole logic board has to be replaced. $500 for a computer I will get rid of the nano-second Apple releases the new iMacs.

That sounds like a ludicrous price to pay just to replace a goofy CPU temp sensor. :(

I'd sure look around for a more reasonably priced repair option.

Unfortunatly I'm in Japan and my Japanese isn't that great so the Apple store is my best option.

I think for that crazy price I'd put up with the fan's speed until I got back to civilized service and a more realistic charge that G-Mo suggested, like ~$60+labour (1 hour).

And a logic board replacement to fix a goofy temp sensor seems a bit much, when even some proper cleaning and new thermal paste application as G-Mo also suggested seems to fix the problem. Heck. you could even do that yourself assuming that they don't charge $100.00 or so for the good paste in Japan!!

I think for that crazy price I'd put up with the fan's speed until I got back to civilized service and a more realistic charge that G-Mo suggested, like ~$60+labour (1 hour).

And a logic board replacement to fix a goofy temp sensor seems a bit much, when even some proper cleaning and new thermal paste application as G-Mo also suggested seems to fix the problem. Heck. you could even do that yourself assuming that they don't charge $100.00 or so for the good paste in Japan!!

question:have you ever disassembled and worked on this model of machine?

It's expensive and annoying, especially for a machine that I'm going to get rid of as soon as the new iMacs are released but I've killed enough Walkmans as a kid to know I shouldn't try to take apart my MBP myself.

As a side I'm so pissed that Apple didn't release new iMacs at WWDC. What can they be possibly waiting for?

question:have you ever disassembled and worked on this model of machine?

Yup, and other similar models.

I've even been into my own earlier Apple MacBook Pro "Core 2 Duo" 2.2 15" model, but not because of any CPU temp sensor problem, and why would you ask the question????

do you know what your 2.2ghz 15" model had that this one doesn't?

Just a quick update to this. I took my MBP in on Thursday and was told it would take about a week to get it fixed but I was pleasantly surprised to get an email from the Apple store today telling me my Mac was ready. The work order shows they replaced the logic board and the heatsink and in a nice surprise they also replaced my battery.

My battery had about 265 cycles on it and could hold about 75% charge, still totally ok for me as I work with it plugged in most of the time. But I was surprised that Apple had gone ahead and replaced the battery for me at no extra charge.

So now everything is back to normal, temps and fans are running normally and I got a brand new battery to boot!

$500 for a new logic board, battery, and labour is quite reasonable.

ps-im still waiting for pm-r to answer my question

ps-im still waiting for pm-r to answer my question

You mean this:

do you know what your 2.2ghz 15" model had that this one doesn't?

I can think of quite a few differences. What particular one were you referring to and why?

I think I also just referred to and confirmed a post from G-Mo to clean and re-apply some new thermal paste.


~$60+labour (1 hour). If you are going to have it opened up, have the thermal paste checked first, if it's dried up it could be causing the CPU to overheat (see it at least once a month); all it would take is cleaning and re-applying the thermal paste and it would be labour only, no parts (unless you are charged for 1/3 a shot of thermal paste).

So, what's your point???

Are you happy now that I've replied to your post???