help with hardware test error code

Discussion in 'iMac' started by faneos, Sep 27, 2012.

  1. faneos macrumors member


    Jul 26, 2012
    When i boot my iMac 27 2009 the cpu fan run full speed i get 0 rpm in stat after i run the hardware test i get this: 4MOT/4/40000002:CPU-0 anyone knows what is it?
  2. Bacci macrumors newbie

    Sep 11, 2012
    4MOT/4/40000002 :CPU-xxx
    CPU fan/blower, located next to left speaker (logic board has to be removed to replace CPU blower)
    Verify that the CPUblower/ fan cable is securely connected to the left side of the logic board and that there are no obstructions that would prevent the blower/fan from rotating. Replace fan if the error continues.
    Normal fan operation, except the CPU blower
    Note: Make sure black mylar tape along the bottom of LCD panel is not obstructing fan blades, if so, cut tape and re-stick to LCD.
  3. faneos thread starter macrumors member


    Jul 26, 2012
    Thanks for the info any chance that logic board cpu sensor or fan circuit damaged?
  4. Bacci, Sep 28, 2012
    Last edited: Sep 28, 2012

    Bacci macrumors newbie

    Sep 11, 2012
    iMacs generate fan errors when rpm is 10% or more off the target rpm.

    I would proceed as follows:

    1/ SMC reset (unplug power cord for a few minutes when imac is shut down), and see if the problem is still there.

    2/ Open it up carefully (following step-by-step instructions on youtube, ...), use a compressed air can to get rid of all the dust and check for anything else that could be straining the CPU fan (like the mentioned tape).

    3/ If the problem persists, buy a new CPU fan e.g. on ebay

    If you don't feel comfortable doing this, seek help

    Good luck!

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