iMac Intel 27". EMC 2309 (Late 2009, Core 2 Duo 3.06 or 3.33 GHz), EMC 2374 (Late 2009, Core i5 2.66 GHz or Core i7 2.8 GHz)

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Apple extended hardware test error codes 4NSN /1/40000000:TH00-9.00

what is mean Apple extended hardware test error codes 4NSN /1/40000000:TH00-9.00

Update (08/24/2017)

iMac 27" 2.66 GHz intel Core i5

Memory 8 GB 1067 MHz DDR3

Mac OS-X 10.6.8

I changed the hard drive with this: WDC WD1005FBYZ-01YCBB1

  • Capacity: 1 TB (1,000,204,886,016 bytes)
  • Model: WDC WD1005FBYZ-01YCBB1
  • Revision: RR04
  • Native Command Queuing: Yes
  • Queue Depth: 32
  • Removable Media: No
  • Detachable Drive: No
  • BSD Name: disk0
  • Rotational Rate: 7200
  • Medium Type: Rotational
  • Partition Map Type: GPT (GUID Partition Table)
  • S.M.A.R.T. status: Verified
  • Capacity: 209.7 MB (209,715,200 bytes)
  • Writable: Yes
  • Writable: Yes
  • File System: Journaled HFS+
  • BSD Name: disk0s2
  • Mount Point: /

more about the new disk :


  • Interface: SATA III 6 Gb/s.
  • Form Factor: 3.5"
  • Windows, Windows Server, Linux και Mac OS.
  • RoHS Compliant: Yes
  • Rate (max) Buffer to Host: 6 Gb/s.
  • Host to/from drive: 200 MB / s.
  • Cache: 128 MB.
  • Rotational speed 7200 rpm.

Please can you help me to understand and fix this problem

Thank you!!!

Answered! View the answer I have this problem too

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What is your system model number? As it has a bearing here on what the correct answer.

Look at the bottom of your systems foot to find the serial number or if you can still access the desktop go into About This Mac and grab the serial number there. Plug it into here: EveryMac - Lookup. Then paste your systems URL here for us to see what you have.


Let's try again... giving us the internal systems specs is not very helpful! We really need the model as you're just given me the internal specs not the system it self.

Think of it this way your listing off the different organs of your body here: lungs, heart, liver. But is that you or just your guts? I need to know you as you not your internals.

Go to the blue link above and plug in your serial number and then paste the system info EveryMac offers here (the URL will do)


URL is Serial Number system?


Your WD Gold HD specs: WD Gold Datacenter HD's

I'm not sure I follow your reasoning on getting this HD as the lower cost WD Blue or the high performance WD Black series should be more than fine here. The Gold series is intended for high I/O within a data center. That's not to say it wouldn't work here it's just overkill on what this system will likely encounter in even the heaviest usage a single person could do.

Until we know what your exact model is this may not be the correct drive.


If we guessed correctly this is your systems specs: iMac 27" 2.66 GHz i5 (Late 2009)


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@ellana - Sadly your system can only support a SATA II (3.0 Gb/s) drive. This drive is to fast for your system.

You will need to find an older drive or one that offers speed sense technology like the Seagate FireCuda. Here is the spec sheet for it: FireCuda 3.5 SSHD. Note the SATA interface lists your system speed unlike the WD drive.

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Thank you Dan ,Really thank you!!! Some "specialists" said it was the graphics card


@ellana - We're not done yet! You still have a second issue as the HD your system had when you bought it had a special sensor cable which we need to replace. Since we don't know what it was we'll need to go with this cable in addition to the replacement drive: OWC In-line Digital Thermal Sensor for iMac 2009-2010 Hard Drive Upgrade


@ellana Now you know where the REAL specialists live and "The Price is Right" ;-)


YES !!!you are Amazing !!!


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Please give us your exact model. Did you change the hard drive?

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iMac "Core i5" 2.66 27-Inch (Late 2009) Specs

Identifiers: Late 2009 - MB953LL/A - iMac11,1 - A1312 - 2374


@danj It's a SATA III and I have not seen where it is backward compatible yet.


@mayer - Are you sure it's a 2009? If it is this drive won't play WD drives are all now fixed SATA III (6.0 Gb/s).


@ellana - Great! So Mayer nailed it.

Don't forget you'll need a bootable drive to re-install the Mac OS and the in-line sensor (see above)


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elen will be eternally grateful.
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