puti_mach

Q: Unusable laptop: CPU throttled to 800MHz with fans running at maximum speed

MBPro Retina, late 2013 running El Capitan

 

The laptop has been running at constant 800MHz for past couple of weeks. Everything is dog slow to the point of unusable. The fan is running at full speed, 6200 rpm constantly. I have tried,

1. Cleaning the dust by opening the back cover.

2. Removing the whole kernel extensions folder

3. Resetting SMC

 

Since the most common cause of throttling is usually temps, I installed iStats and checked the reported temperatures from the sensors and discovered something interesting:

 

Th1H NB/CPU/GPU HeatPipe 1 Proximity  -128.0°C
Ts0P Palm rest L  32.6875°C
Ts0S Memory Bank Proximity  -128.0°C
Ts1S Unknown  -128.0°C
TA0P Ambient temperature  -128.0°C
TBXT Unknown  37.296875°C
TB0T Battery TS_MAX  37.296875°C
TB1T Battery 1  37.296875°C
TB2T Battery 2  34.6875°C
TCGC PECI GPU  40.0°C
TCSA PECI SA  41.0°C
TCXC PECI CPU  39.6875°C
TC0C CPU 0 Core  37.0°C
TC0E CPU 0 ??  39.71875°C
TC0F CPU 0 ??  39.96875°C
TC0P CPU 0 Proximity  -128.0°C
TC1C Core 1  38.0°C
THSP Unknown  -127.0°C
TH0a Unknown  36.875°C
TH0b Unknown  37.125°C
TH0c Unknown  -127.0°C
TH0A Unknown  36.875°C
TH0B Unknown  37.125°C
TH0C Unknown  -127.0°C
TH0F Unknown  -13.65625°C
TH0R Unknown  -44.125°C
TH0V Unknown  -128.0°C
TMLB Unknown  -127.0°C
TM0P Memory Slot Proximity  -128.0°C
TPCD Platform Controller Hub Die  -128.0°C
TW0P AirPort Proximity  -127.0°C

Some critical sensors like CPU/GPU proximity and Ambient Temp sensors are reporting a value of -128.0°C. This is probably the reason because from I checked in one of my friends MBPro and these values are reporting normal in their laptop.

 

Is there any way to disable or fix or write fake values to these sensors? I do not really care about bricking the device since in its current state, it's not of any use.

MacBook Pro with Retina display, OS X El Capitan (10.11.5)

Posted on Aug 8, 2016 11:05 PM

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Q: Unusable laptop: CPU throttled to 800MHz with fans running at maximum speed

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  • Helpful answers

  • by OGELTHORPE,

    OGELTHORPE OGELTHORPE Aug 9, 2016 4:21 AM in response to puti_mach
    Level 9 (52,113 points)
    Mac OS X
    Aug 9, 2016 4:21 AM in response to puti_mach

    Your best option is an appointment at a Apple store genius bar for a FREE evaluation.

     

    Running Apple diagnostics might give you a clue:

     

    https://support.apple.com/en-us/HT202731

     

    Ciao.

  • by Allan Jones,

    Allan Jones Allan Jones Aug 9, 2016 7:34 AM in response to puti_mach
    Level 8 (35,044 points)
    iPad
    Aug 9, 2016 7:34 AM in response to puti_mach

    I'm seeing a suspicious mix of positive and negative temperature values. I also see repeated identical values to the decimal point, such as

    36.875; -127.0; -128.0; 37.296875; -128.0; etc. There is no way to have negative values at room temp. That suggests:

         a) the logic is so bricked that many of of the sensors can send out other than error values, or

         b) iStat has a problem.

     

    I would share that report with the iStat developers to see if they have seen such a collection of repeated and negative values before.

     

    Does the computer function at all? Have you opened it up for any reason? When someone opens a Mac., sensor damage can occur but not to the extend your reprot shows, so thata question is simply a long shot to get and much diagnostic info as possible.