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Repair guides, support, and troubleshooting information for MacBook Air models with 13-inch displays.

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Battery Power OK But Battery Not Dectected...

I have an A1466 MacBook Air 2017 model that is having some quite odd issue....

I have followed everything in this post battery not detected please help! to no avail.

So, The customer brought it from me in perfect working order with a new battery 1 week ago and today they came back to me saying it is shutting down when disconnected from the AC. So this is what I have done to see wht this issue is:

0 - Connect the AC I get green > orange light which is a good sign.

1 - Took out the battery and power on for 10 seconds to reset SMC.

2 - Connected with no battery to see if it boots (No Battery icon displayed)

3 - Connected with battery THE UNIT BOOTS INTO OS (It shouldn't boot)

4 - Tested with 2 different new & used batteries (Same results as in (3)

5 - Booted into recovery mode (No Battery icon displayed)

6 - Booted into OS with battery connected & AC connected (No Battery icon displayed)

6 - Booted into OS with battery & AC connected (No Battery icon displayed) BUT when I disconnect the AC the unit stays on! so power is going from the battery to the board and it stayed on for 30 minutes until I shut it down)

7 - About this mac & coconut battery do not detect any battery at any time.

Conclusion: The system is NOT booting unless it is connected to the AC in.

The system did shut down if disconnected (Highly likely from low battery)

The system is not detecting the battery even though it is running solely from the battery power.

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I am stumped on what this can be? I/O Board is my 1st thought.... the main board and I/O show no signs of any blown fuse. I was going to do a fresh install but seeing that the battery has no icon in the menu bar in recovery mode (It does on other units I have here to compare). Am I the only one to have this ever happen and what can be the cause and solution. The system (Monterey) is VERY slow to load up..... I currently have it 'On charge (Orange light is there and am waiting to see if it fully charges the battery to green without any battery icon or recognition in the system. Calling upon the experts @oldturkey03 & @danj to assist.

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@livfe did you ever get this resolved? What was the outcome?

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@oldturkey03 It is still in the repair shop, Tech guy traced a short to the SMC and also the SMC will be replaced as it was not responding to well he said.... I guess 7 days more and we will see if it is resurrected.

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@livfe excellent. I do hope that they will tell you exactly what they replaced/fixed. I have a suspicion and just would like to see if I was close :-) Keep us informed.

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@oldturkey03 The SMC Chip is on order and we will see if that fixed it if not then I will just scrap it for parts.

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The batteries BMC logic is either bad or the data lines from the battery to SMC are damaged.

I would try a spare battery to test things.

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@danj I have tried with 3 different new quite new and old but working condition batteries as previously mentioned.

I spoke to my tech guy here and we believe it is something with the data lines that carry the battery info.

I have had it on charge for 2 hours and still on orange. It did shut down when disconnected but earlier it stayed on when disconnected from the AC. It cannot be an issue with the batteries themselves as they are all fine.

If anyone can point to me where and what needs to be replaced it could save me £50 if I did it myself.

What could have caused this fault to develop, I would love to know.

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@livfe - Then you have a logic board circuit level issue within the MOSFET's as well! The error NaN is telling us the BMC micro-controller is not talking to SMC! But SMC is working! As it sees the Charger is connected.


Did this system have a liquid spill? I would do a deep inspection and trace out the SMC input data lines.


I did note you didn't do a full SMC reset. Give that a try to be sure something is not hung. The proper way is to disconnect the battery and anything else connected to the ports (MagSafe too) now press and hold the power button for a good 15secs, then plug back in the MagSafe charger. The system should spontaneously startup, let it finish booting and to a clean shutdown then plug the battery back in. Does Coconut tell you anything new?

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@danj I did the SMC reset as you said above maybe 3 times during the 1st disgnostics. There was no liquid spill. Are you from the UK?

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@livfe - Some of my family is, I'm in the States.

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@danj Is this problem repairable?

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