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My Macbook Air (2018) Retina battery has depleted within 130 cycles. I was running Windows via Bootcamp in heavy load, letting it discharge fully and charge repeatedly. If I unplug from power source the system shuts down. Battery status is showing as "replace now". Coconut Battery test shows that current capacity is 9 % of design capacity. The system when connected to AC power turns on but it is running extremely slowly. When checked activity monitor, Kernel_Task shows 300 % of CPU. Apple Diagnostics test revealed one issue PFM006 - SMC issue. I tried resetting SMC, PRAM. Issue still exists. My questions are

  1. Is PFM006 (SMC) related to Battery. If battery is replaced, will this issue go away? Else could it be a faulty temperature sensor?
  2. Is the Kernel_task issue related to PFM006 (SMC)?
  3. Could there be any relation between these three events (PFM006, Battery, Kernel_Task)?
  4. Does apple diagnostics cover all sensors? If PFM006 is the only error returned, does that mean all sensors are working fine?
  5. How is it possible for a battery to depleted within 130 cycles when it is guaranteed as 1000 cycles?

Note: All apple service centers are closed due to COVID-19. So trying to find the issue online.

  • Gosh, there's a lot of questions there! :) Let's see: (1) It could be related to the battery, but may not be, so there's no guarantee that replacing it will solve the problem. (2) The kernel task certainly isn't causing the error, but it could be responding to it to protect your Mac from damage. (3) Yes. (4) Apple Diagnostics is not as thorough as I'd like it to be, but then again thorough diagnostic testing takes a long time, so Apple is just providing a basic tool here. The PFM006 error is not prescriptive - it just means there may be an issue with the System Management Controller. – Monomeeth May 28 '20 at 11:00
  • (5) The battery is not guaranteed for 1,000 cycles. While it's true your MBA battery has a life expectancy at or around 1,000 cycles, it's not uncommon for batteries to exceed or fall short of this number; it's just an estimation of how long it can last. But, if the battery has failed at 130 cycles, it is definitely unexpected! This usually indicates a faulty battery or some sort of damage (usually from liquid or moisture, or from a potential shock such as being dropped). My strong recommendation would be to call Apple on the phone and see how you go from there. – Monomeeth May 28 '20 at 11:02
  • @Monomeeth Thank you. My warranty has expired and apple support is unavailable. – gokul May 28 '20 at 11:57
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    I would say, sleep on this question or take a walk. Pick the first most key question and ask a follow up question that’s one clear question. Let’s get that answered. Then come back and edit this to have one less question to answer. I can’t +1 it as useful, but I won -1 either. #5 is one I could answer if asked clearly. @ me if you spin that nice objective question off. – bmike May 28 '20 at 21:19
  • I asked the same question in iFixit after I asked here. Got a comprehensive answer. ifixit.com/Answers/View/637637/… This might be useful for someone. – gokul May 29 '20 at 8:26

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