MacBook – CPU System agent core (TC0E/TC0F) running very high

hardwaremacbook propower-management

When my MBP (Retina, 13", Early 2015, identifier MacBookPro12,1) is under load, could either be CPU load or "bus-load", ie wifi, usb, webcam etc the CPU System Agent Core-sensor shows a very high temperature. The SMC-key is either TC0E or TC0F (ie Tango Charlie Zero Echo / Foxtrot). With very high temperature I mean 90C+, and I start to get bus errors here.

I believe this is either due to faulty SMC cooling "instructions" or bad application of coolant paste. I'm leaning towards bad application of coolant paste.

Is there any way I could easily check this? I guess I would void warranty by actually opening the MBP?

If you want to test your temperatures compared to mine:

-- At first, get homebrew, see instructions at
-- after installing run
> brew cask install istat-menus
-- thereafter
-- scan for all sensors
> istats -scan
-- add the two which go high for me to default set
> istats add TC0E
> istats add TC0F
-- check default + added sensors
> istats

Best Answer

    1. I would do a SMC reset (google on apple)
    2. In addition to iStat, i have Macs Fan Control.
    3. just use iStat to DISPLAY fan speed and CPU gfx core temp
    4. Use Macs Fan Control, MFC, to control fan speed. By default, my mbp's fan will not come on, and often doesn't even when way beyond 45C!
    5. in MFC drop down menu... Right Side - Sensor-based... Change control...
      • Sensor-based value: GPU PECI
      • Temp that fan speed will start to increase from: 30C - 80C
      • OK to confirm change
    6. I believe MFC is a linear fan curve, as temp increases, fan speed will also go up. I prefer it this way. Lost my last mbp to lousy fan control, not happening this time.
    7. my MFC just shows fan icon in menu bar, but no fan speed or temp info.
    8. Remember in MFC's preference... set it to autostart

    Im out and about quite a bit with my mbp. I use a hard shell case from iPearl (search on Amazon... our model is A1502). Its got little legs I can prop up the rear of my mbp, to keep it cooler. Fits well, no issues here, I am typing on it right now.

    mbp 13" retina 12,1 blah blah, ~1900 rpm, 35C

    As far as CPU System agent core on my mbp, iStat will report it to be 0 at times, then it'll resume back to normal in a sec or two. Let me know if u figure out that one. thx.