2.5 GHz dual-core Intel Core i5 processor (Turbo Boost up to 3.1 GHz) with 3 MB shared L3 cache.

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Hardware test shows error "4SNS/1/40000000: IO0R-1.550"

After the kernel_task process started taking up too much CPU(like 500-1000%) and the system hangs, this happens randomly. I ran the AHT and the error shows up

"4SNS/1/40000000: IO0R-1.550"

Figured out this is a sensor issue (SNS) but didn't find any resource mentioning the IO0R code.

Does Anyone know what this code refers to?

PS: My camera is also not working says "No video capture devices were found." in System info

Update (05/20/2016)

I think I found the issue. I opened up my macbook for cleaning up (lot of dust). And disconnected the iSight camera cable. Now the Hardware test passes without any error.

Answer this question I have this problem too

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sadly apple does not share the information

But SNS is a sensor issue


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1 Answer

It's likely a problem with one of your current sensing resistors on the board. These can be replaced. Requires some micro soldering.

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Thanks for answer. I thought this was current sensor issue but then I read carefully it says IOzeroR not IzerozeroR. Which seem like I/O port issue or something. I'm just guessing here though.

And if micro soldering solution is not in my reach, would this mean a logic board replacement?


Not all the time

you could take it to apple and they will most likely tell you whats wrong and give you a quote

you can use this to your advantage as if its something silly that can be replaced with in 5-10 minutes that you are happy to do then you have saved yourself a bit of money

if it comes to a logic board replacement ( highly doubt) apple charge a fair price but you can get it worked on or buy a replacement and do it yourself


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goutham will be eternally grateful.
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