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Released June 2012, Model A1278. Intel processor with Turbo Boost, Up to 512 MB DDR5 Video RAM

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Error: 4SNS/1/40000000: ICOR - 21.925


When I run the Apple Hardware Test on Macbook Pro 13" 2.5 GHz 2012.

It shows me error 4SNS/1/40000000: ICOR - 21.925.

Could you explain me what wrong with my mac?

Thanks for your answer.

I understand that my logic board has problem with system sensor.

But, when I try to run AHT test again it shows me the same error but the last number is different all time.

What is this number and why is this number different each time?

Answered! View the answer I have this problem too

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2 Answers

Chosen Solution

Here's a good reference: How to invoke and interpret the Apple hardware tests. I had to use my ASD lookup to get ICOR error.

So if we take your error: 4SNS/1/40000000: ICOR - 21.925 and break it down this is what we have:

4SNS System sensor

ICOR CPU 1.05 V Rail Average Current - Mac Mini (Early 2009)

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Yes, the last digit will likely be different each time you run AHT. Its the current value. really not important here. The I in the error message is current.


It's time for a new logic board


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The "21.925" number at the end will change each time because that is the temperature it recorded during the diagnostics test.

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If this was a temp error then the value is the temp. Here it's a Voltage rail issue (ICOR) so the value is voltage.


You're right and I apologize for not seeing your initial answer to OP.

While I have you, I have a similar error:

4SNS/1/40000000: TAOP-42.398

I've found that this is a bad ambient air sensor. My fans are spinning constantly, even at idle. The computer is fairly cool at touch. Would removing the ambient air sensor resolve this? Or does it need to actually be replaced?


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greytl will be eternally grateful.
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