kernel_task causing issues yet again!

[ethan-1878]

Hi all,

*IN A NUTSHELL*​

• 2012 non retina MBP is experiencing kernel panics
• kernel_task using up 300%+ CPU
• have tried multiple 'fixes' (see below)

I've always experienced issues with kernel_task on my MBP (mid-2012 9,2) since I upgraded the RAM and Optibayed it. Since then I have took it to an Apple store and had a Genius take a look at it - everything came back as fine and working properly.

As some of you will know, the kernel_task issue sucks up 300-400% CPU and causes the fans to run at full speed 24/7. Not only does this result in a painfully slow/unusable Mac, it actually makes a pretty horrific noise. This time around, it's happened at the worst possible time. I'm a DJ and have a gig this saturday so no MBP means no gig with in turn means no money to get MBP fixed.

Here's what I've tried so far:

• Reset PRAM
• Reset SMC
• Done a clean install of Mountain Lion (through Internet Recovery, I was running the latest public release of Yosemite - 10.10.3)
• Ran a terminal command which moves the SMC kext out of a kext bundle into my home folder

All of the above have work for me in the past just not in any particular order.
I haven't got any peripherals connected to my Mac.
Since Resetting PRAM and SMC, my keyboard backlighting has stopped working and System Preferences doesn't have a backlighting section in the keyboard menu.

Please don't give me the usual "Oh it's the upgrades that you did which are causing kernel panics" because since they have started happening, I have replaced all of the original hardware back into my mac (including the superdrive) and I still get kernel panics.

Sorry for the rather wordy post but I thought details might be important in finally getting to the bottom of this really annoying issue.

Thanks in advance for any help.

 

[chrfr]

2012 non retina MBP is experiencing kernel panics

Do you have logs from the panics?
Also, moving system extensions is a bad idea and may be responsible for some of the issues you're now seeing.

 

[ethan-1878]

Not that i know of - where are they usually stored?

I've moved the kext's multiple times in the past and it's fixed my problem without any nasty side effects although I am aware that I shouldn't really be moving system files about.

 

[ethan-1878]

Do you have logs from the panics?

Not that i know of - where are they usually stored?

Also, moving system extensions is a bad idea and may be responsible for some of the issues you're now seeing.

I've moved the kext's multiple times in the past and it's fixed my problem without any nasty side effects although I am aware that I shouldn't really be moving system files about.

 

[ethan-1878]

Had an appointment at the Genius Bar today. They confirmed that there is a fault with the Palm Rest temperature sensor - that explains the fans spinning up, one down, one to go - after further delving into the sensor reports, the Apple Genius also found that I have a faulty ambient light sensor - there's the explanation for my nonexistent keyboard backlighting.

I've left my MBP at the Apple Store for repair and was advised it would take 3-5 days for them to complete the service. I'll be sure to check back when they call me and let you all know how successful their fix is.

 

[ethan-1878]

Checking back in - the Genius Bar have had a representative liasing with me for the past 2 days. He explained that they originally thought that the issue was related to the trackpad (£70 repair) so they replaced that for me and there was no change. The next port of call was to replace the top cover (£120) this never worked either. This means that the last possible component that could cause such an issue is the logic board. So the Apple Genius has replaced my logic board (£380) and they're currently running the post-repair tests to confirm whether or not the logic board has definitively repaired the issue - it can't really be anything else.