Left fan constantly runs full speed - no load, no overheat
My late 2013 MacBook Pro took a Coke spill right into the keyboard about a year or so ago. The machine returned to gook working order after a while (despite keys that can be somewhat sticky from time to time). Recently, however, the left fan has begun running at full speed constantly. SMCFanControl right now reports it at 6846, and this doesn't seem to fluctuate at all. The fan begins this behavior immediately after bootup, even before the Apple logo appears. This has happened once or twice in the past, but after a short while the fan returned to normal.
The system is not under any CPU load whatsoever, and this happens with the laptop on a hard and flat surface. The left fan seems to be the only one affected.
I ordered and installed a brand new left fan, just to rule out an issue with the fan itself. Same behavior - full speed ahead.
The last 3 of my serial are D59.
I would suspect that this could be related to the sensor(s) being compromised in the spill, but I don't know where to look to check them, clean them, or anything else.
Can anybody give me any pointers or next steps?
Is this a good question?
8 Comments
Give 820 number of your board, which is written on logic board so we can find the proper ASD test for your laptop. A sensor has failed which is causing this behavior.
by zzz
Where would I find the number on the logic board? I just want to know where I'm looking when I take it apart again. Thanks!
by LordSavage
https://d3nevzfk7ii3be.cloudfront.net/ig...
See the picture above.
To the left from the battery connector, you have a small rectangular sticker with white writing. That's your Logic Board's S/N. But, the unit's S/N should suffice. Written your Mac's bottomless. Starts with "C02".
Either way.
It sounds like a temperatur sensor in your top case is dying, and making your fan go nuts. Well known issue amongst technicians.
I can't remember at this time (3:40 am where i am), if the 2012 Retina's can run AST2, but i'll check my own tomorrow, and if it works, i'll give you a heads up, and we can run it together at some point. That should pinpoint which sensor is making a fuss.
by MorbidMylar
You have most likely damaged a temp sensor near the cooling fins of the heat sinks.
The easiest way to see what the issues might be is to have an ASD test run on it.
Im willing to bet 99% its a temp sensor.
by chriswku03
S/N from the case bottom is C02MG1W4FD59 but if you happen to actually need the number off the logic board I'll crack it open again and get that. Since I'm using the laptop right now, S/N was by far the easiest to get to.
I will note that running an Apple Diagnostics ("D" at bootup) showed the following, but you guys may be honing into a more precise diagnosis than this…but I'll give this in case it provides more info:
* Reference Code: PPF004
* Additional reference code: PPF003
Thanks to all for the "thus-far" diagnosis!
by LordSavage
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