MacBook Air: kernel_task high CPU %, fan on but no heat?

[nancykc]

I've been experiencing this problem for 2 days now.
This is the general sequence of events:
(1) Computer crashed, wouldn't turn on, yet charger light on when plugged in.
(2) Built-in keyboard and trackpad usable prior to log-in as well as in recovery mode, but frozen in own account. USB mouse worked, however. Also even though it was fully charged and plugged in, the charge read as "X" and warned me to charge immediately.
(3) Extremely slow/frozen functionality & fan constantly audible immediately upon power on. No heat however.

At the genius bar my MacBook was still dead (unresponsive to power button) so the guy couldn't do much. It was also non-responsive to an SMC or NVRAM reset (seeing as it wouldn't even turn on). He however did open up my MacBook and looked at the hardware and said everything "looked fine." I'm assuming this means he checked the fan for dust as well?

When I took it home (devastated) I fiddled around a bit more, tried an SMC reset. Tried being patient, etc. Somehow got it working back to normal!

But today, the problem persists. Extremely high CPU % for kernel_task, hardly any usage from any other application (just in case, I deleted VirtualBox and Adobe stuff - no luck), constantly audible fan, and no heat whatsoever.

Do you guys have any insight on what could be causing the problem (to me it seems like hardware, but the "genius" said it was fine...) or how I could fix it?

Anyway I think I will take it for a second genius opinion.


Some general information:
MacBook Air (13-inch, Mid-2013)
Running OS X El Capitan 10.11.5
13.07 GB free

 

[chscag]

Take it back to the genius bar for that second opinion. I don't understand how the tech came to the conclusion that everything looked fine unless he was referring to the fact that he couldn't see if anything was wrong. You don't have much free space on your SSD which will definitely make the machine work harder moving the swap file and memory around. If you have an external bootable hard drive you might try booting your MBA from that to see how it behaves.

 

[nancykc]

Hi,

I found this on another forum and it seemed to work for a lot of users:
"1. Go to About this mac under the apple in the upper left and click on More info
2. Click on system report
3. make a note of what it says after Model Identifier
4. go to your master drive – System -Library – Extensions – IOPlatformPluginFamily.kext -Contents – Plugins – ACPI_SMC_PlatformPlugin.kext – Contents – Resources – find the name from step 3 and move it to a folder that you can find again if needed.
3. Restart and you’re done"

Probably inadvisable to mess with system files, but since it worked for so many others I tried it. Instead of MacbookAir6_2 I moved the MacbookPro6_2 file since the air one didn't exist. Upon restarting and doing an SMC and NVRAM reset (again probably inadvisable because now I don't know which change I made actually caused the results) kernel_task was back to normal CPU %, and the Activity Monitor looked normal. But the fan is still on high, the battery reads as 0%, and I can't seem to make battery level show on my toolbar (clicking the checkmark in system preferences yields nothing.)

I will move my files to create more space. How much would you suggest...?

 

[Slydude]

Most of our members recommend keeping roughly 15 - 20% of space free on the boot drive.

 

[nancykc]

Thanks for the help.

I am keeping now around 16-18% free space on the drive. The problem persists.
Even when kernel_task is at normal CPU % levels, the fan goes on. SMC and NVRAM resets accomplish nothing apparent except prevent my laptop from powering on for hours at a time - I had to wait 10 hours, trying every 2 hours to no avail, before my laptop turned on again.

Moving the .kext file back resolved the battery issue but back again is kernel_task (200-300%) and as always, the fan. Temperature varies between 70 and 100 degrees Fahrenheit.

Does this sound like a software or hardware issue? Is there any way I can avoid the $280 for whatever is causing these problems?

 

[Slydude]

Are you sure those temperature readings are in Fahrenheit? 70 - 100 degrees Fahrenheit shouldn't be causing the fans to go berserk.

I'm sure the others will have some ideas but the bit about having to wait two hours or more between power ups disturbs me a bit.

 

[nancykc]

Hi all, just a quick update on my situation.
I ended up not taking it for a second opinion.
I re-installed the OS X while in recovery mode (took about 3 hours lol) and now everything is good as new!

 

[nancykc]

I retract my statement, lol. Within 24 hours the same problems came back. After a week of observation my MBA vacillates between 2 problematic states:
(1) Battery not recognized, normal CPU activity, does not turn on for several hours after shut down or SMC reset. Fan constantly audible.
(2) 200-300% CPU usage of kernel_task, slow functionality (due to kernel_task). Fan constantly audible.

Apple Support has recommended that I visit the Genius Bar again or do a complete erase and re-install of an older version of OS X.

 

[lclev]

I agree a trip to the genius bar is needed. But why would they recommend installing an older version of OS X? That makes no sense to me. I am currently typing this post on the exact same model of Macbook Air you have. I am running OS X 10.11.5 with 4GB of memory and 125GB of free space on the SSD. I have none of the issues you are experiencing. I don't think it is El Capitan. I think it is a hardware issue.

Just my 2 cents worth. ;D

Lisa

 

[Slydude]

I agree Lisa. The long delay between startup attempts shouldn't be necessary if this were a software issue. I'm also curious about the reported temps. Something is wrong there. If the temps are accurate, 70 - 100 degrees Fahrenheit should not be causing the fans to go nuts.

Edit: I'm wondering if there isn't an issue with one of the thermal sensors. If i t is reporting the temps as higher than they actually are wouldn't that cause the system to shut down? That wouldn't explain why the wait between restarts needs to be so long.

 

[ferrarr]

Do you have a current backup of your system? I would do an erase and install of the OS. You can start up from Recovery mode, go into Disk Utility and erase the drive/partition as needed. Then close Disk Utility, and Install the OS.

I am assuming that when you were in Recovery mode, you only installed the OS without erasing the hard drive first.

 

[yazzflute]

Did you ever figure out what was happening? Having the same issue on the exact same machine...