Sensor Error during Apple Service Diagnostics

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Sensor Error during Apple Service Diagnostics

I've been having problems with my early 2009 mac pro freezing and having to hard reboot. I ran Apple Service Diagnostics and the test fails during Sensor tests:

Temp (TNOD) - (MacPro) IOH or (iMac or mac mini) MCP, Tdiode (test 1) - Sensor Reads Within Operating Range

- Check to ensure that sensor reads within operating range.

ERROR - Sensor is reading above the high limit

- TEST FAILED -

Does this mean I need to replace the logic board?

Mac Pro, OS X Mountain Lion (10.8.2), Early 2009 Mac Pro

Posted on Nov 12, 2012 2:44 PM

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Answer 1

Nov 12, 2012 4:07 PM in response to tricksters

Users have reported that some of the sensors are field replaceable for not much money. Others have reported that the cable was loose, and re-seating the cable was all that was required.

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Answer 2

tricksters Author

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Nov 14, 2012 5:14 PM in response to Grant Bennet-Alder

Any idea how I would identify the sensor in question? I looked for a diagram of the logic board but didn't turn up anything.

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Answer 3

Jan 3, 2013 11:39 AM in response to tricksters

I have the very same problem... Any updates?

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Answer 4

tricksters Author

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Jan 3, 2013 8:24 PM in response to Daniel Pherson

I ended up getting a new logic board and installing it. However I should have inspected my existing one first. The issue was that the heat sink sensor had come loose. One of the pins that secures it to the logic board had broken so it was only partially connected.

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