MacBook (13"): More sudden shutdown commentary; faulty temperature sensors

We continue to report on an issue we've covered extensively in recent weeks: sudden, seemingly random shutdowns exhibited by various MacBook (13") models. First, a recap of our coverage:

• MacBook (13"): Possible hardware fix for sudden shutdowns
• MacBook Special Report: Sudden shutdowns -- possible fixes
• MacBook (13"): More on sudden shutdowns
• MacBook (13"): Suddenly shutting down

Faulty Temperature sensors The prevailing theory for the cause of sudden shutdowns, after much deduction, is that some logic boards have a faulty temperature sensor which incorrectly senses a high internal temperature, then shuts the system down in an attempt to prevent hardware damage.

MacFixIt reader Pete Rock writes:

"The idea of faulty temp sensors rather than the machine actually running "hot" is appealing for several reasons. In my case, there was no real evidence that the problem occurred because of a truly hot MacBook as the problem would occur randomly and without the MacBook feeling hot, or the fans running. Sometimes the shutdowns would occur when the machine was clearly not hot. Also, the sudden shutdowns sometimes occurred during the boot process which probably excludes software problems, corrupted preferences etc. "

"(I suggest) people with this issue should take their machines in for repair and use the words 'sudden shutdown.' My experience suggests Apple is aware of this symptom. The tech that examined my machine didn't even bother with asking about software etc. He went right to stressing the machine by loading applications to get processor usage as high as possible.  Apple does seem to have as part of its diagnostic toolkit for this problem resetting PRAM and the PMU, neither of which helped in my case.

"Finally, I experienced excellent service and turn-around time from Apple for this issue after taking it to a local Apple Store. I couldn't be more pleased with how it was handled."

Feedback? Late-breakers@macfixit.com.

Resources