I just started having problems with my Mid 2011 Mac Mini — it's fan is continously on although the computer temperature is relatively low and not a lot of CPU is being used. I'm very nervous about this because my last Mac Mini died due to overheating issues.

I realize this may be a common problem, but I specifically would like to know about two keys that appear when I run iStats:

$ istats scan
Scanning keys...

Tp0C Unknown  43.45°C  ▁▂▃▅▆▇
TA0p Ambient temperature  40.38°C  ▁▂▃▅▆▇
TA0P Ambient temperature  40.38°C  ▁▂▃▅▆▇
TA1p Ambient temperature  34.63°C  ▁▂▃▅▆▇
TA1P Ambient temperature  34.63°C  ▁▂▃▅▆▇
TCGc PECI GPU  59.0°C  ▁▂▃▅▆▇
TCGC PECI GPU  59.0°C  ▁▂▃▅▆▇
TCPG   98.0°C  ▁▂▃▅▆▇
TCSc PECI SA  50.0°C  ▁▂▃▅▆▇
TCSC PECI SA  50.0°C  ▁▂▃▅▆▇
TCTD Unknown  0.16°C  ▁▂▃▅▆▇
TCXc PECI CPU  57.19°C  ▁▂▃▅▆▇
TCXC PECI CPU  57.19°C  ▁▂▃▅▆▇
TC0c   53.0°C  ▁▂▃▅▆▇
TC0d   51.0°C  ▁▂▃▅▆▇
TC0p   46.13°C  ▁▂▃▅▆▇
TC0C CPU 0 Core  53.0°C  ▁▂▃▅▆▇
TC0D CPU 0 Die  51.0°C  ▁▂▃▅▆▇
TC0E CPU 0 ??  58.81°C  ▁▂▃▅▆▇
TC0F CPU 0 ??  62.41°C  ▁▂▃▅▆▇
TC0G CPU 0 ??  94.0°C  ▁▂▃▅▆▇
TC0J CPU 0 ??  1.59°C  ▁▂▃▅▆▇
TC0P CPU 0 Proximity  46.13°C  ▁▂▃▅▆▇
TC1c   56.0°C  ▁▂▃▅▆▇
TC1C Core 1  56.0°C  ▁▂▃▅▆▇
TI0p Unknown  38.25°C  ▁▂▃▅▆▇
TI0P Unknown  38.25°C  ▁▂▃▅▆▇
TI1p Unknown  36.5°C  ▁▂▃▅▆▇
TI1P Unknown  36.5°C  ▁▂▃▅▆▇
TMBS Unknown  50.0°C  ▁▂▃▅▆▇
TM0p Unknown  40.0°C  ▁▂▃▅▆▇
TM0P Memory Slot Proximity  40.0°C  ▁▂▃▅▆▇
TM0S Memory Slot 1  40.8°C  ▁▂▃▅▆▇
TPCD Platform Controller Hub Die  45.0°C  ▁▂▃▅▆▇
TP0p Unknown  43.25°C  ▁▂▃▅▆▇
TP0P Unknown  43.25°C  ▁▂▃▅▆▇
TW0p Unknown  38.25°C  ▁▂▃▅▆▇
TW0P AirPort Proximity  38.25°C  ▁▂▃▅▆▇

Done scanning keys.`

As you can see everything is a somewhat normal temperature except for the TCPG and TC0G keys, which are close to 100 degrees Celsius. Would anyone be able to tell me what these keys are, and how I could address this issue?

  • Did you try to open it and remove the dust from the inside?
    – claudio
    Oct 11, 2017 at 14:19
  • It's dust-free, and I'm keeping an eye on it — but I found out that because I switched out the harddrive for an SSD, a couple of thermal detectors are not connected properly and are therefore reading the high values. In actuality the temperature is fine.
    – chmod
    Oct 17, 2017 at 16:34

1 Answer 1


The reason why I'm getting really high readings is because I'm using a third-party SSD which doesn't have Apple's thermal detectors included.

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