Mid 2012 MacBook Air Random Shutoff

Question

Level 1

13 points

Mid 2012 MacBook Air Random Shutoff

I've been trying to find a solution for over a year now. My MacBook air has been shutting off randomly with no warning.

At first I figured it was overheating, so I installed Macs Fan Control and cranked the fans up, but it still shuts off around 60-70°C CPU temp which should be fine. The first 3 years I owned the computer I never had a single issue and the fan only ever sped up to where it was audible 2 times.

The error code in the log files is Previous Shutdown Cause -2, which I can't find a description of anywhere.

I took the computer to the Genius Bar for a hardware check but the computer shuts off as soon as they attempt to run the test. They wanted to change the logic board for $600+ so I said I'd think about it.

Has anyone experienced this? I cannot find any confirmed solutions online and am not sure if I should replace the logic board or the i/o board first. When it powers off it is like it lost power. Immediate shut off. It won't reboot for at least 20 seconds and if I turn on before a couple minutes it will shut off again before I get to the desktop screen. Yet it will work flawlessly sometimes for up to an hour or so.

The computer has been babied its whole life and never been dropped or spilled on. Looking inside it looks fine, but tbh I'm not sure what I would look for.

If anyone has any ideas at all I'd love to hear them. It is a mid 2012 Air i5 with 4gb RAM.

EDIT: Also I have performed SMC resets, this did not solve the problem.

MacBook Air (13-inch Mid 2012), OS X El Capitan (10.11.5), null

Posted on Jul 3, 2016 4:44 PM

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Answer 1

OGELTHORPE

Level 9

57,329 points

Jul 4, 2016 4:05 AM in response to mcfetty

How does the MBA operate if you start up in Safe Mode?

https://support.apple.com/en-us/HT201262

If you can, run an Apple Hardware Test:

https://support.apple.com/en-us/HT201257

Note that an error free AHT is not conclusive.

Check if there are any kernel panics recorded. If so, log and post it per these instructions:

https://support.apple.com/en-us/HT201753

Ciao.

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Answer 2

mcfetty Author

Level 1

13 points

Jul 6, 2016 3:09 PM in response to OGELTHORPE

Thanks for the reply!

I have done an AHT in the past and the only way to get through without shutting down was by putting a fan up to the notebook. I will run again though and check out everything else you have mentioned.

Thanks again.

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Answer 3

John Galt

Level 10

156,260 points

Jul 24, 2016 6:03 PM in response to mcfetty

Previous Shutdown Cause -2

There is no publicly available documentation explaining the meaning of those codes, but a negative Shutdown Cause is generally understood to indicate hardware failure. That supports the Apple Store diagnosis you already received.

The only exception to the above that I can personally confirm is -128, which occurs after a firmware update. That code may not apply to all Mac models.

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Answer 4

mcfetty Author

Level 1

13 points

Jul 24, 2016 6:39 PM in response to OGELTHORPE

So I finally got around to trying out your suggestions. Sorry for the slow reply.

In safe mode it seemed fine for a while so I started opening a bunch of apps to stress out the cpu and also plugged it into power. It did end up crashing -- Does this mean I can rule out a software issue? Upon restarting a few minutes later the cpu core temp was at 72 degrees C (I did not use fan controller when in safe mode).

I attempted to run an AHT but the computer crashes during the "checking logic board" phase. I'm not sure if its crashing because its checking the logic board or because it happens to get too hot by that time.

As for kernel panics, there doesn't seem to be any evidence of them occurring. I searched the log files for "panic" and came up with nothing.

Previous Shutdown Cause: -2 continues to be the log file after every crash however I cannot find anything about it anywhere on the web.

Any other ideas? I with I knew what the -2 meant but maybe I'll just have to start throwing parts at it.

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Answer 5

mcfetty Author

Level 1

13 points

Jul 24, 2016 7:09 PM in response to OGELTHORPE

I found this post that blames -2 on upgraded memory. This is the first time I've noticed this but in activity monitor it says I'm consistently (like a perfect line) using 3.3gb (of 4gb) of RAM with literally only 3 tabs of safari open. Does this not seem like a ridiculous amount of RAM to be using for such minimal use? Could it be crashing when RAM use exceeds the 4gb available?

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Answer 6

John Galt

Level 10

156,260 points

Jul 24, 2016 8:06 PM in response to mcfetty

The tests you performed all support Apple's conclusion that the logic board has failed. It's up to you to determine whether the $600 replacement cost is economically justified.

72°C is well within its normal operating temperature.

It's also normal for OS X to use all available system memory.

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