MacBook Air 2015 11" Fan Runs on Full, CPU Throttling

Hi,

I’m trying to fix a MacBook Air 2015 11”, which has its fan running on full and is throttling its CPU. I believe this issue may be related to a faulty temperature sensor.

I’ve run Apple Diagnostics, which says there may be an issue with the SMC, error code PPN001 and PFM006. I’ve also installed TG Pro, which shows that there may be an issue with the hard drive sensor.

So far, I’ve replaced the SSD (after the hard drive sensor issue reported) and cleaned the Macbook internally and replaced the thermal paste.

What should be my next step? Is this likely to be an issue with a sensor on the motherboard, or is it worth swapping out the trackpad/MagSafe board? Is there any other way of detecting the faulty sensor?

Thanks for your help!

Ben

Hi, thanks for your suggestion and sorry I've taken a few days to get back to you.

I've carefully inspected the motherboard again, and there is no visible corrosion anywhere on the board, or near the SMC chip. However, there was something covering a small component near the SMC chip, which I cleaned off with IPA - this may have just been dust! The whole board has also been cleaned with IPA, and unfortunately this has not helped.

I’ve attached photos of the motherboard, including the before and after of the dirty component.

Have you got any other suggestions for locating the faulty temperature sensor?

Thanks!