Fan running at full speed, CPU throtled

This seems to be a fairly common issue but with various causes and I can't seem to find the cause on my laptop. I understand that the fan running at full speed and CPU throttling often point to a faulty temperature sensor. I'm using the program TG Pro to check sensors, and it's telling me that the HD sensor may not be working correctly. I replaced the SATA cable (where I believe the sensor is located) but no luck. I've tried a different hard drive, a solid state drive, with no luck. I got fed up and went ahead and replaced the logic board, figuring this would surely solve the issue. Still I'm getting the full blast fan and throttled CPU. Any ideas? What else could it be? Is there a HD temp sensor that is located somewhere other than the SATA cable, logic board, or HD itself?

I will note that when I boot into safe mode, the fan still runs at full speed but the CPU throttling goes away.

Answer this question I have this problem too

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There is a Video from Lois Rossmann about that

https://www.youtube.com/watch?v=3w4j_-JW...

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Thanks. Good video but it doesn't address my issue. He's fixing a motor control for the fan. My issue stems from faulty temperature sensors.

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This is most likely your trackpad. Since you replaced your board and HDD cable there is not much left. Before replacing your trackpad, download Macs Fan Control and see what your battery temp sensor is reading. Normal is anywhere from room temp and up but nothing over 50. Your looking for some crazy reading like -144 or something of that sort. Your trackpad has a temp sensor and is a fairly common issue.

Update (09/08/2017)

Also check your HDD temp in the same program. Again... Look for crazy temp values.

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Thanks. Macs Fan Control is a nice program I didn't know about. But it's showing normal temps for all sensors. There's not even a crazy reading to indicate one might be bad (this is what I've seen from similar programs). Here's a screenshot: http://i703.photobucket.com/albums/ww37/...

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I'd replace your trackpad. That's pretty much the only practical sensor left. There is a chance that it is another sensor on the board but I doubt it. Replace your trackpad and you should be good.

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That's a good thought if it's the only sensor I haven't replaced. I just unplugged the trackpad from the logic board and started the computer (doing an SMC and PRAM reset), but the issue remains. Wouldn't this indicate that it's not the trackpad sensor?

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No. That will not work. If the trackpad is not connected it will refer to the same state that it would be in if a sensor failed.

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Gotcha. I'm ordering a trackpad now to give it a try.

I mentioned before that I'm using TG Pro to read sensors and it's telling me that the HD sensor may not be working correctly. This is strange to me since I replaced the SATA cable. Is there some other HD sensor? I also thought that maybe the used cable I purchased is also bad, but the chances of that seem low.

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Hi I think the pram or smc reset fixes this maybe it's a pref if the first two don't work try restarting in recovery mode command r... and see if it fixes it that will tell you its software if not you could be a goner but I'm not a tech at all!!! But I did have this on one or more of my mbp

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Thanks. I should have mentioned that I did several pram and smc resets after replacing the logic board. I don't think this is a software issue as I've wiped the stock HAD and even tried putting in a different HD.

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Hi there i have the same mac and I have the same problem but power button don´t works the light on keys don´t work the fans are 100% cpu kernel task uses 200% cpu. I allready change the disk for 1 ssd install last version of OS sierra but no luck I try tu update smc it says that update but when i see version is the same. the power button works when i made key combination like option + comand + power so is not hardware fault . i have the web cam broken can be from there? is there any solution please help me this is my first mac and Im regreted all ready

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