Fan always on full, mac slow, I believe it thinks it’s overheating

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MacBook Air 13寸 2017年维修指南

在2017年6月，Apple更新了13寸的MacBookair，他换上了更新更好的Intel Core i5处理器，让性能和电池续航时间提高。

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Kai Mcpherson @kaimcpherson

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发帖于: 2022年3月23日

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Fan always on full, mac slow, I believe it thinks it’s overheating

Hi, I recently bought a MacBook Air 2017, it wouldn’t let me install os so i booted into a external usb and installed from there, however the whole time the fans were on full, I guessed it might be because of the missing software but it didn’t stop after, tried all the usual bug fixes, such as smc reset, nvram reset etc, no difference, on a bench mark it scores around a third of what it should, I saw a thread suggesting trying to turn it on without the trackpad cable and battery connected, so I tried that, no difference, however now the trackpad and keyboard do not function, however the power button still works?

Any ideas how I can go about fixing this? It’s very clean inside, no rust or even dust, and what I believe to be the original battery only has 30 cycles on it, so it’s barely been used from what I can gather.

I might try reseat the trackpad cable again tomorrow in case it helps get the keyboard and trackpad working again

Oh, I forgot to add, I did a diagnostic on it before trying to disconnect the cables, results were PFM006 and PPN001. Also tried safe mode and had the same issues

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Did you try running the onboard diagnostics? Restart your system and press the D key to enter. Let us know what the error message is

Reference: Mac startup key combinations

If you can you may also what to install a good thermal monitoring app like: TG Pro even the trial version can be useful. Take a snapshot of the main window and post it here for us to see 在已经存在的问题里加入图片

由 Dan 完成的 2022年3月23日

I tried diagnostics, above I posted the error codes, and I also tried macs fan control, there I could get the fans to turn down but the performance was still throttling, all of the thermal sensors were fairly cool and looked normal, I checked them

And all appeared to be working - temperatures fluctuated on all sensors

由 Kai Mcpherson 完成的 2022年3月23日

@kaimcpherson - I don't find MacsFanControl that useful as it doesn't offer enough diagnostic info. Please give TG Pro a try as it has what I need.

PPN001 error is telling me you have a bad sensor but without seeing what TG Pro tells us.

由 Dan 完成的 2022年3月24日

@danj

Hi, apologies for the delay, thanks for your help with this. I installed the trial and added the photo of the main page, do I need to include any other info from it?

Thanks again

由 Kai Mcpherson 完成的 2022年4月18日

Hi Kai,

This likely could be a broken pin/not connected sensor causing this. I have a friend who has a 2017 mba and I'll ask him if he's had a similar behaviour.

由 Nick P 完成的 2022年4月18日

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Did you try running the onboard diagnostics? Restart your system and press the D key to enter. Let us know what the error message is

Reference: Mac startup key combinations

If you can you may also what to install a good thermal monitoring app like: TG Pro even the trial version can be useful. Take a snapshot of the main window and post it here for us to see 在已经存在的问题里加入图片 — Dan
I tried diagnostics, above I posted the error codes, and I also tried macs fan control, there I could get the fans to turn down but the performance was still throttling, all of the thermal sensors were fairly cool and looked normal, I checked them

And all appeared to be working - temperatures fluctuated on all sensors — Kai Mcpherson
@kaimcpherson - I don't find MacsFanControl that useful as it doesn't offer enough diagnostic info. Please give TG Pro a try as it has what I need.

PPN001 error is telling me you have a bad sensor but without seeing what TG Pro tells us. — Dan
@danj

Hi, apologies for the delay, thanks for your help with this. I installed the trial and added the photo of the main page, do I need to include any other info from it?

Thanks again — Kai Mcpherson
Hi Kai,

This likely could be a broken pin/not connected sensor causing this. I have a friend who has a 2017 mba and I'll ask him if he's had a similar behaviour. — Nick P

Nick P @np_f1_2021 声誉积分: 1.6千 14 7 1 · Answer 1 · 2022-03-23T17:10:08-07:00

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Nick P @np_f1_2021

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Morning Kai,

This sounds to me like a certain sensor has broken or is at an unreasonable value. This means you’ll need to check the voltage. if this computer was brand new and is having issues then you should be under consumer law (Unless u arent in Australia) but otherwise sounds like a thermal sensor issue.

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Dan @danj 声誉积分: 478.9千 Self employed contract worker 35 329 970 · Answer 2 · 2022-04-20T17:47:05-07:00

Dan @danj

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@kaimcpherson - Sorry for not responding sooner, I've been very busy the last few days with the marathon

This is starting to look like a tach logic within the logic board needs repairs. Here's the logic which needs to be checked

You need check these two components

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Thanks for that, what I’m going to do is disconnect the logic board from everything and test again to see if it’s anything external, and I’ll look at the board whilst it’s out, what side of the board would I be looking at? Left / right above / below? I can’t quite make sense of what part of the board is in the photo. Thanks again !

由 Kai Mcpherson 完成的 2022年4月27日

@kaimcpherson - The backside top corner near the fan. It's possible you got some liquid damage which entered in through the heat sink fins.

I would just take the logic board out to inspect it, disconnecting things won't help you in isolation of the fault here. But before you go down that path do you have the needed tools and skills to resolder the SMD devices? If not I would look for someone locally that does.

Follow this guide MacBook Air 13" Early 2015 Logic Board Replacement which is the same for your system.

由 Dan 完成的 2022年4月28日

Thanks for that, I will have a look and post here after

由 Kai Mcpherson 完成的 2022年4月29日

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MacBook Air 13寸 2017年维修指南

Fan always on full, mac slow, I believe it thinks it’s overheating

Update (03/23/2022)

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