I have problem with SMC in MacBook Air 2016. While running on battery, data from SMC module freezes. In iStat Menus temperatures from sensors, RPMs, current meters and voltage meters from CPU aren't refreshing. Also fan sometimes switches on high RPM and runs continuously, even when laptop is quite cold. When I plug in charger, fan goes back to 1200 RPM and temperatures are being normally refreshed. I had this issue propably even before updating to Mojave. I tried resetting SMC, but nothing happens. What is the possible reason for this issue?
MacBook – SMC sensors failure while running on battery
batteryhardwaremacbook propower-managementtemperature
Related Solutions
I understand your concerns (justified or not), you love your Mac and want to keep it alive as long as possible.
Here are some home remedy (Do it Yourself)-- (also available where you live).
If you want to keep your Mac cooler during HOT games, go to pharmacy and buy what they call a gel-pack (gel balení). Freeze it!
Then put it under your Mac with a towel in between (to prevent freezing).
That will provide additional cooling for few hours. Have second gel-pack if you want to continue gaming for 24 hours a day :)
As for your temperature reports, so far they look normal based on this example.
Throttling
This test wouldn't be complete if we didn't address the subject of throttling. Prime 95 and Furmark can extract the maximum performance out of the hardware. When both programs are run simultaneously, the core frequency drops (caused by Prime 95) to 1.2 Ghz. Running Prime 95 alone, we measured temperatures between 92 and 104 degrees Celsius (197.6 and 219.2 degrees Fahrenheit), and the word "Throttling" flashes repeatedly in HWiNFO. Furmark on its own cycles through all available Turbo Boost steps. After about one hour, the temperature settled at a fairly consistent 85 degrees Celsius (185 degrees Fahrenheit) with the fan system running. We never measured above 100 degrees Celsius (212 degrees Fahrenheit) with Furmark. This limitation might be due to the power adapter: in the above scenario, the system would require 86.6 watts - but the power adapter can only supply a maximum of 85 watts. Immediately after running our different tests, we subjected the system to 3DMark 06 and CineBench R11.5. The results were identical to after a cold boot.
The fastest way to quick check is to use the surface temperatures as shown here.
In the Apple Support article on SMC reset it reads "On MagSafe power adapters, the LED might change states or temporarily turn off when you reset the SMC.". Other than that SMC reset does nothing visible. So probably the reset is working.
It seems like the battery is dead. In that case the Mac will throttle the CPU to reduce power consumption. This explains also the high load. Since the battery is necessary to buffers peak loads, the MacBook relies on it to operate properly.
You must replace your battery.
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Best Answer
You've already reset the System Management Controller, which was the first thing to try, so I would probably start with testing to see if this behaviour is replicated when booted into Safe Mode and if the issue persists then running Apple Diagnostics.
Boot into Safe Mode
Follow these steps to boot your Mac into Safe Mode:
If the problem doesn't occur while booted into Safe Mode, let me know and we'll go from there.
If the problem persists, proceed with running Apple Diagnostics.
Run Apple Diagnostics
Follow the steps below to run Apple Diagnostics:
Note: If pressing and holding the D key at Step 3 doesn't work, start again at Step 1 and, at Step 3 press and hold both the OptionD keys instead. This will try and run diagnostics from the internet instead, so you will need to allow more time for it to complete.
Regardless, take a note of what happens and let me know how you went.