E2015 MBP CPU Frequency throttled, fans not running

[Jon Newman]

Hi all, I've been looking for a post with this problem but can't find one with the same symptoms. My Early 2015 13" 2.9Ghz MBP (High Sierra) has started throttling the CPU to 1.3Ghz at all times from boot, and the fans are not running at all automatically (0 rpm), even when I try to open a usually processor-intensive game for a while. The Mac will open the game but it runs at slow speed, so the temperature stays below 70C even without the fans. I guess this is what the Mac is trying to achieve by throttling to 1.3Ghz?
iStat Menus can't seem to get the fans working manually, but 'Macs Fan Control' can manually kick them off if I pull the slider to ~4k rpm. I've reset the PRAM and SMC a couple of times, no change. I've even opened the mac and cleaned the fans.

Any ideas what may be the issue here? Is it just OSX 10.13 throttling because it's an older macbook or is there something else at play here?

I live outside of US/EU so visiting an Apple Store is impossible at the moment.

 

[Audit13]

Is a long shot but try a fresh install of High Sierra by deleting and re-creating partitions.

Is also possible that there is something wrong with the thermal sensors.

Was the MacBook dropped or exposed to liquids?

 

[maximit]

That is exactly why I love the 13 models. The 2015 and newer will completely shut down the fan and run silent, that is by design. It will also throttle down the CPU when not needed. If you want to stress test the CPU and fans, open terminal and type "yes > /dev/null & yes > /dev/null & yes > /dev/null & yes > /dev/null &". Watch the CPU and fans then, they will max out.

 

[Jon Newman]

That is exactly why I love the 13 models. The 2015 and newer will completely shut down the fan and run silent, that is by design. It will also throttle down the CPU when not needed. If you want to stress test the CPU and fans, open terminal and type "yes > /dev/null & yes > /dev/null & yes > /dev/null & yes > /dev/null &". Watch the CPU and fans then, they will max out.

Thanks. I ran the yes command for about 10 minutes and the attached screenshot shows that the temperature is still <50C, the CPU frequency is still 1.3Ghz and the fans are not spinning.
Only other issue I'm having is my battery is pretty knackered and needs replacing. Would that influence the CPU management to throttle the frequency?
Thanks again.

 

[maximit]

The battery could influence it... did you try running the test plugged into power?