Fan keeps running even in sleep!

[DreamSeason]

I've manually set my fan to run at ~3000rpm. I didn't notice that before. But yesterday I happened to put my ears near the fan and much to my surprise I heard the fan running! Even my mac is sleeping. Is it a bug or something else?

[Steven]

DreamSeason
It shouldn't happen. Can you give me some more info?

[DreamSeason]

DreamSeason
It shouldn't happen. Can you give me some more info?

What do you need? I had posted diagnostic info before. Here they are again.

Code: Select all

Macs Fan Control 1.3.0
MacBookPro12,1
Intel(R) Core(TM) i5-5257U CPU @ 2.70GHz[100]
Mac OS X Unknown

Fans:
Right Side-min{1299}curr{2993}max{6199}mode{1,3000}


TempSensors:
TA0P (Ambient) - 36, 36
TB0T (Battery TS_MAX) - 31.3984, 31.3984
TB1T (Battery Point 1) - 31.3984, 31.3984
TB2T (Battery Point 2) - 30.3984, 30.3984
TBXT () - 31.3984, 31.3984
TC0C (CPU Core 0) - 51, 51
TC0E () - 53.0938, 53.0938
TC0F () - 54.7617, 54.7617
TC0P (CPU Proximity) - 45.75, 45.75
TC1C (CPU Core 1) - 51, 51
TCGC (PECI GPU) - 50, 50
TCSA () - 51, 51
TCXC () - 51.0312, 51.0312
TH0A () - 34.125, 34.125
TH0B () - 34.125, 34.125
TH0C () - 34.125, 34.125
TH0F () - -1, 206.125
TH0R () - -1, 206.125
TH0V () - 34.7812, 34.7812
TH0a () - 34.125, 34.125
TH0b () - 34.125, 34.125
TH0c () - 34.125, 34.125
TH0x () - 34.125, 34.125
THSP () - -1, 129
TM0P () - 42.25, 42.25
TMLB () - -1, 129
TPCD () - 47, 47
TW0P (Airport Card) - -1, 129
Th1H () - 38.375, 38.375
Ts0P (Left Palm Rest) - 30.875, 30.875
Ts0S () - 35.043, 35.043
Ts1P () - 30, 30
Ts1S () - 34.6836, 34.6836
Ts2S () - 33.1289, 33.1289


Disk drives:
APPLE SSD SM0256G - 34.125

[Steven]

DreamSeason
1. Does it happen every time you put the macbook into sleep mode?
2. What if use another RPM setting (e.g. 2000 RPM)?

[DreamSeason]

DreamSeason
1. Does it happen every time you put the macbook into sleep mode?
2. What if use another RPM setting (e.g. 2000 RPM)?

1. I am not sure if it happened every time. I just notice that yesterday because I set it to 3500(i rarely did that) which is audible. To be honest, even around 3000rpm, it's not easy to hear.
2. I am afraid 2000 is not spinning enough to be heard.

[DreamSeason]

DreamSeason
1. Does it happen every time you put the macbook into sleep mode?
2. What if use another RPM setting (e.g. 2000 RPM)?

I am afraid it happened every time I put mac into sleep. I just did another test again. As long as I manually set the RPM to a audible speed, I could hear the fan spinning even when mac is in sleep. To solve this, I have to wake my mac up and reset to auto.

[DreamSeason]

DreamSeason
1. Does it happen every time you put the macbook into sleep mode?
2. What if use another RPM setting (e.g. 2000 RPM)?

hi, Steven. I'd like to share my discoveries with you.
The reason why the fan would turn on even when sleep mode may be quite surprising. The AC adapter!

If you put your macbook into sleep mode without AC, later you plug the AC in. The fan would turn up if you set it to a fixed RPM speed in MFC.

[Steven]

DreamSeason
Wow. Looks like MFC should turn the fans to auto before going to sleep, right?

[DreamSeason]

DreamSeason
Wow. Looks like MFC should turn the fans to auto before going to sleep, right?

I am afraid you misunderstood it. Most of the time, I set the fan speed to 3000RPM. So entering sleep mode mac will turn off the fan completely. But if you plug in AC adapter during sleep, the mac would turn on the fan which is set to 3000RPM by MFC. According to console, the AC's plug in indeed waked the mac up. Same goes to other ways of waking mac like pressing a keydown etc. All in all, if you set the fan to a fixed speed, it will resume that speed once mac is waken no matter which ways the mac is waken.