Early 2011 model, A1278 / 2.3 GHz i5 or 2.7 GHz i7 processor.

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MacBook Pro CPU Temperature Sensor Error?

So I just bought a broken Macbook Pro 13" 2.3ghz i5 2011 thinking it was just running extremely slow and having glitchy graphics because of a failed hard drive, but after verifying the hard drive, that does not seem to be the problem. I also checked the RAM, by switching out the memory with another set, and reinstalled OSX. So then I finally ran the Apple Hardware Test, and received this error:

4SNS/ 1 /C0000008: TC0D--124

Which I looked up and it's the CPU Temperature Sensor. So I ran Fan Control and I got this read out:

left fan:6,196 RPM

Right fan:-1 RPM

Temp: -198 F

So I've reset the PRAM and SMC, and nothing has worked. Do you guys have any ideas? Is there anyway to replace this sensor? Is this the reason why my Macbook Pro would be running so extremely slow & glitchy?



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You might have a SATA cable problem.

This model has had a run of bad SATA cables which causes the CPU to work harder as it has to do a lot of retries (causing it to overheat). Sluggish performance would also support this problem.

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Are you talking about the sata cable from the hard drive?


Yes, there was a bad run of SATA cables. As you stated the system was very slow and glitchy that can explain your problem here. It would be what I would replace first as the CPU is going into over drive trying to read/write to the HD were the data fails CRC it needs to retry to read/write causing the CPU & HD to run much hotter than it would normally.


I just checked the cable, no luck, still runs slow. Any ideas?


checked or replaced?


I replaced it.


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I've seen this elsewhere. I am having same problems. Haven't tried trackpad solution yet, but getting ready to go see tech to see if they can fix it. Read here for more information:

Where is the left palm rest temp sensor?

Hope this helps.

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Given the other symptom of the system being extremely slow I don't think thats the issue here.


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Michael will be eternally grateful.
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