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Fan Speed Problem on MD318LL/A

Hello


Im currently working on a MD318LL/A.


The problem is that the fan is very loud.


After some poking around i have discovered that only the left fan is running a high RPM ( around 7k+)

The right fan is sitting around 2k


The temps seem fine and the cpu is not under load.



What could be causing this issue?


I have already reset the SMC.

MacBook Pro, OS X Mountain Lion (10.8.5)

Posted on Oct 8, 2015 11:01 AM

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Oct 8, 2015 11:02 AM in response to N0way

Something is not right. Possibly one of the fans has died or a sensor has failed. Please make an appointment at the Apple Retail Store - Genius Bar and take it in for service. If you are not in the USA or cannot set up an appointment this way, then contact your local Apple Store directly.

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Oct 8, 2015 11:21 AM in response to N0way

I did not say the fan has died. I said that was possible. Unless you have taken the cover off you cannot verify a fan is running based on a third-party utility.


No, sensors cannot be replaced directly. They are usually on the motherboard or on a component that is connected to the motherboard.

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Oct 8, 2015 11:33 AM in response to Kappy

Yes i have taken of the back cover.


I just physically replaced the problem fan with a replacement i have on hand and its still revving up on boot.


Must be a sensor thing.


Im asking if the temp sensor is a soldered component or one that is replaceable.

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Oct 8, 2015 1:02 PM in response to OGELTHORPE

Yes actually just ran the quick one returned "4MOT/4/40000002: Left side - 7101"


Running the extended one as we speak.


Looked this code up and could not find any info on the exact code.


I did find a "4MOT/4/40000002: Left side - 0" post that suggests that the fan motor is failing, but as stated above i have already replaced the fan with the same problem occurring. In fact I even put the old fan in another MD318 and it is working just fine.



The fan is currently over-revving and i have read that if the fan is running past 10% of its designed rpm it will return this kind of error.


I believe this is the case.


Problem is that even with a 3rd application i cant get a signal to the fan to turn down the rpm.


All of this makes me think there circuit failure on the logic board.


However, could it still read the RPM of the fan if this is the case?





EDIT


Just finished the extended hardware test returned same error


Shocking I know..

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Fan Speed Problem on MD318LL/A

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