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Fan starts running at 3600RPM with 44 ºC

5655 Views 60 Replies Latest reply: Jan 5, 2014 3:36 AM by mkirke RSS
  • MadMacs0 Level 4 Level 4 (3,320 points)
    Currently Being Moderated
    Jul 3, 2012 12:20 PM (in response to René Bijloo)

    René Bijloo wrote:

     

    I am now scanning wit ClamXav for virus, last time was six months ago or so. It will take some hours i guess, afterwards i do the resets. ClamXav has found some 20 virus in my e-mail folders for now. Could this affect to the fans or sensors?

    No. I suspect they are just possible phishing attempts. Just don't allow ClamXav to quarantine or delete the files as that will corrupt your mailbox index(es). Always use your e-mail client to inspect these files and delete them from there if necessary. That applies to all A-V software.

  • oursjean Calculating status...
    Currently Being Moderated
    Jul 5, 2012 12:56 AM (in response to René Bijloo)

    Hi everybody,

     

    I have the exactly same problem, same datas for all fans, same GPU diode temp (6°)…on iMac alu 24" (8.1) running under Lion.

    I launched a AHT yesterday, wich give me that error code: 4SNS/1/40000001:TGOD-7.875

    Regarding some other forums, it seems the logicboard is damaged .

    In my case, the trouble happened after moving the iMac from my home to my office (by car).

    It looks like the only way to fix it is to replace the logicboard…

    Can someone confirm ?

     

    Thanx to all of you…

  • LostAccount Calculating status...
    Currently Being Moderated
    Jul 5, 2012 1:40 AM (in response to oursjean)

    Hi

     

    I am really sorry to hear this.

     

    I can't speculate on the exact error code offered by AHT but an SNS component in the string certainly relates to a sensor or in a worst case scenario the SMC itself, which lives on the Main Logic Board. One thing is clear, ignoring it can potentially further damage your mac. Don't despair, it could be a hard drive or optical disc sensor for example.

     

    Unfortunately, Apple does not publicly document AHT errors, in specific instances they refer to them as in this unrelated link, http://support.apple.com/kb/TS2081

     

    If you happen to find the error code in full length using Google it will likely come from an unofficial source.

     

    I have to encourage you to bring your mac in to an AASP or Apple Retail Store for an evaluation (visit the retail store page before going to a retail store, a prior appointment might be necessary), apple.com/retail They should be able to tell you more on what the string means after an evaluation.

     

    If you contact AppleCare you may still be under warranty or be entitled for a free repair under their protection plan or a repair extension program. Even if you are outside phone support they are still obliged to help you find the nearest service point.

     

    I don't see anything related but take a moment to see if Apple has any repair extension programs open, just go to apple.com/support and you will find on the bottom left corner a cluster of links titled, "Exchange and Repair Extension Programs". Click on "All Programs". Usually these are covered even if you are outside warranty.

  • MadMacs0 Level 4 Level 4 (3,320 points)
    Currently Being Moderated
    Jul 5, 2012 2:35 AM (in response to oursjean)

    oursjean wrote:

     

    Hi everybody,

     

    I have the exactly same problem, same datas for all fans, same GPU diode temp (6°)…on iMac alu 24" (8.1) running under Lion.

    I launched a AHT yesterday, wich give me that error code: 4SNS/1/40000001:TGOD-7.875

    Regarding some other forums, it seems the logicboard is damaged .

    In my case, the trouble happened after moving the iMac from my home to my office (by car).

    It looks like the only way to fix it is to replace the logicboard…

    Can someone confirm ?

    I had a similar issue with an older iMac G5 where the temperature sensor connector was not seated properly. I doubt that's your problem, but worth a check and certainly cheaper than replacing the logic board.

  • angaros Calculating status...
    Currently Being Moderated
    Sep 4, 2012 3:09 PM (in response to René Bijloo)

    Hi,

    I'm experiencing the same problem with the same iMac (2008, Core 2 Duo 3.06GHz), fan is always at max speed and GPU Temp shows 6ºC.

    Apple Hardware Test gave me the same error that oursjeans showed a few post before  (4SNS/1/40000001:TGOD-7.875).

     

    Did you solve the problem? How? Was it a Hw issue? If so... Expensive?

     

    Thanks in advance!

  • oursjean Level 1 Level 1 (0 points)
    Currently Being Moderated
    Sep 4, 2012 11:53 PM (in response to angaros)

    Hi everybody,

     

    I solved the issue.

    I send back my iMac to Apple,

    Hopefully it was not the logicboard, but the Graphic card wich needed to be replace.

    Regarding some other forums, It seems that this model nVidia 8800GS often crashes on iMacs.

    The cost of the GC today is around 150€, I paid 135€ more for the replacement.

    Today iMac is runing normally again…

     

    I hope this will help all of you!

    Thx

  • angaros Level 1 Level 1 (0 points)
    Currently Being Moderated
    Sep 7, 2012 8:14 AM (in response to René Bijloo)

    Thaks for the info.

    I'll do the same, let's see what happens.

     

    After all 200-300€ is not too much, isn't it?

  • John C Zonum Calculating status...
    Currently Being Moderated
    Nov 11, 2012 8:31 AM (in response to angaros)

    @angaros, did you replace the nvidia graphics card? If so, what was the outcome? I have the same problem as you, 6 degrees C on the GPU diode temp, CPU ran running at max rpm, 3,600. Would love to hear your outcome.

     

    Thanks.

  • John C Zonum Level 1 Level 1 (0 points)
    Currently Being Moderated
    Nov 11, 2012 12:35 PM (in response to John C Zonum)

    After 1 day of searching, I have a solution to the symptom, not the problem.

     

    My Imac24 (mid summer 2008) Intel Core 2 Duo 3.06GHz, 4GB RAM, OSX(10.8.2) w/ the NVIDIA GeForce 8800 GS 512 MB graphics card is showing an unrealistically low temp on the GPU Diode of 6 degrees C w/ a CPU fan running at max rpm of 3,600. Even when the CPU is 99% idle, the fan runs at 3,600, all the time, unless I turn the computer off or put it to sleep. This started about 2 weeks ago. Here's a screen grab from a great little app named, istat pro

    Screen Shot 2012-11-10 at 7.56.21 PM.png

    I've tried everyting I've read in the forums except for running the AHT (can't find my disk and the D and option D solutions don't work). Nothing worked. I think the problem is a bad temp sensor on the GPU diode as my IMac is fine, except for the CPU fan being on all the time.

     

    Just a few minutes ago I stumbled across this thread, https://discussions.apple.com/thread/2554924?threadid=2554924 and saw the solution to my symptom--a way to actually slow the fan down--written by Jez DK. His solution is genius, send a command to smcfancontrol (download that at http://www.macupdate.com/app/mac/23049/smcfancontrol) that limits the upper limit of the CPU fan. By default, smcfancontrol lets you set the minimum fan speed, but for people with the problem of the CPU fan spinning like crazy when heat is low, we want to slow the fan down. So, install smcfancontrol and issue the following command:

    /<path where smc is installed>/smcFanControl/smcfancontrol.app/contents/resources/smc -k F2Mx -w 12c0

    That line limits the fan to 1200 RPM. I set my limit to 1400 and here's what istat pro is showing now:

    Screen Shot 2012-11-11 at 1.26.47 PM.png

    Like I said, this is just fixing the symptom, not the problem. Given that my IMac is 4 years old and is backed up every day, I think this is the best way for me to go. I'm not going to plunk down hundreds of dollars to get this sensor fixed. I may try to do something with automator to see if I can automate the fan speed a bit, so when things do heat up, I'd like to have the CPU fan spin faster than 1400 RPM, kind of like what would happen if the sensor were working ;>

  • MadMacs0 Level 4 Level 4 (3,320 points)
    Currently Being Moderated
    Nov 11, 2012 12:54 PM (in response to John C Zonum)

    I've had similar problems involving the hard drive heat sensor on two occassions, both of which I repaired myself.

     

    One was simple. I just reseated the sensor plug on the logic board end and everything went back to normal.

     

    The second was with the same sensor, but in replacing the hard drive, the sensor itself was damaged. I was able to obtain a replacement sensor assemply for a few bucks locally (although the first one they sold me was too short).

     

    I suspect my iMac G5 may be easier to work on than yours and your sensor may not be as easily replaced.

  • angaros Level 1 Level 1 (0 points)
    Currently Being Moderated
    Nov 19, 2012 1:51 PM (in response to John C Zonum)

    Hi, no I didn't...

    I'm using the same method you've described, that's smcfancontrol and it's working ok.

    But I want to take the iMac to the technical service to fix the problem, just need some free time ;-)

  • LostAccount Level 1 Level 1 (80 points)
    Currently Being Moderated
    Nov 19, 2012 2:51 PM (in response to John C Zonum)

    Hi John

     

    Even without running AHT, we already know the issue is hardware.

     

    I gather you have already performed an SMC reset, sorry but this looks like a long thread so I apologize in advance if I am repeating previously offered steps.

     

    If you have, reducing fan RPMs, as you said is clearing the problem and not the symptom.

     

    I just want to throw a word of caution. To make a long story short, do get it serviced, find time. Until then, make sure that the iMac is not overheating as it could be a safety hazard - in other words keep your eye on it. I doubt anything will happen, God fobid but it's best to be safe.

     

    I hope this helps and I hope you find time to get the unit diagnosed.

     

    Kind regards

  • angaros Level 1 Level 1 (0 points)
    Currently Being Moderated
    Nov 21, 2012 12:17 AM (in response to LostAccount)

    By the way... I never slow down rpm too much, usually I set it to 2500, it isn't too noisy and I think it's better than 1200-1500 rpm. Anyway I must take it to the service as soon as possible.

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