MacBook Pro models with 13" displays

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MBP Crashes all the time. AHT Error 4SNS ICOC?

Hi everybody!

My MBP is crashing all the time while booting. Even when I use the MacOSX Install disk.. it`s crashing. I see the Apple Logo and the rotating ball for some seconds and then it`s crashing.

Then I started Mac Hardware Test. In the detailed Test my MBP crashes and when I start the standard Test while checking the logic board it stops and the message:

"Alert! Apple Hardware Test has detected an error.

4SNS/1/40000000: ICOC-48.730"

I took a pic of it if you want to see it.

I tried all shortcuts at startup. I tried with several hds and rams.

I didn`t find anybody who had the same problem with "ICOC-48.730" extension :(

Do anybody got an idea of what it could be?

Thanks in advance &




OK.. dont need to answer anymore. This error indicates some faulty temp sensors and now it`s completely gone.

Topic closed :)

Answered! View the answer I have this problem too

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What was the source of the logic board and just how confident are you that it works?



thanks for reply.

I bought it at ebay from selling company (jkcomputerparts). I`m not really confident :) they told me it passed their quality tests. It`s under warranty so i`m able to change it, but i thought maybe anybody could say what this error means in detail, i had some hope to get it fixed.


I re-installed really everything veeeery carefully. Also checked heatpipe and thermal compound and all connections and cables, everything is fine.

After I was ready the macbook booted one time into MacOSX.. but I directly started again because I wanted to run it through AHT.

When the macbook was running for several seconds it`s gettin warm (normal temp, not hotter than usual) and then it won`t boot anymore.

Even hardware test won`t start.. direct shutdown.

Then I give it some minutes to cool down and tried again.. Then I came into AHT and run the test. First time it shut down, second time it worked with the same error as result.. just a different variable at the end ICOC-52.757 instead of ICOC-48.730


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1 Answer

Chosen Solution

After some research, the news isn't good from what I've read. That error code basically means your machine is dead. Again, that is just what I read. Does the machine get really hot?

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@Skippy722 1st thanks for your quick reply. No the board isn`t hot and the fan is rotating... This is a replacement board because my original one was broken by water. I changed the upper case incl. keyboard and added a new DC-board and last but not least the logic board. I think I installed everything correctly and worked with earthing on my hands.


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