Mid-2009 Hardware Test Error

Discussion in 'MacBook Pro' started by 121a, Sep 14, 2013.

  1. 121a macrumors newbie

    Joined:
    Sep 14, 2013
    #1
    Hello everyone, new to the forum but not new to tinkering with computers. I have had my Mid-2009 Macbook Pro 15.4" with Duo 2.53ghz for the last three+ years and it has been a good computer. The most expensive repair was a top case a while back for $250. For the most part I was able to do all other repairs myself (SuperDrive repair/upgrade to SSD/replace SuperDrive with a HDD caddy). Up until recently it functioned perfectly. Now it still does except the fan.

    A week ago the fan just out of the blue, spun up to its max of 5,700rpm. No reason. Temperature of the CPU is 98F-100F using smcFanControl. Performed an AHT and it returned the following problem:
    4SNS/1/40000000: TC0D- 128.000

    I accidentally interpreted this to be a palm rest temperature sensor and replaced the trackpad today. Well, now the fan is randomly spinning up and down from 2000-5700. It is extremely annoying and other than the noise, the computer functions just fine. I would like to get it silent again. Any ideas what can be causing this odd occurrence?

    From what I have read, it is a CPU temp sensor, but my sensor readout is not fluctuating. I have reset the SMC and PRAM multiple times, nothing helps. Is there something loose or is something much harder to fix happening?

    Thanks!
     
  2. nerfologist, Sep 16, 2013
    Last edited: Sep 16, 2013

    nerfologist macrumors member

    Joined:
    Jun 14, 2013
    #2
    Hello,
    I own a MacBook Pro 15" mid-2009 2.66 GHz. I have been experiencing a fan issue similar to yours ever since mid-2010 (1 month after the warranty expired) :(

    In my case, some of the temperature sensors will drop to a ridiculously low value (likely the result of an overflow), then the readings disappear completely.

    I include a reading of iStat with temperatures (notice some are missing) and fan speeds (both maxed out at 6200 rpm).

    [​IMG]

    Do you have a similar situation?

    In my case, it should be due to defective temperature sensors on the logic board. Based on my research, they are not replaceable. A logic board substitution is currently beyond economic repair, as I'm keeping the money for my next Mac.
     

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