Question Fan error on boot

[vasco.martins.drummer]

Hey guys!

I’ve recently installed an Arctic Freezer 33 Plus on an ASUS B450M Plus Gaming.

After connecting the fans to each other and connecting to the motherboard, I’ve noticed that the cpu fan connector is 4 pin as usual, but the connector from the fan only had 3 pins.

Both fans run when booting, but it won’t go past post unless I disable the smart control speed system in the bios.

Thanks in advance,

Vasco Martins

 

[Barty1884]

The connector to the board should be 4 pins, as should one of the fans be?
The second doesn't matter, as via the splitter, it's controlled by the primary fan.

33's have a zero RPM mode, which will generate a warning if they're zero upon boot. With that cooler and zero RPM functionality, disabling the warning is the only option.

 

[vasco.martins.drummer]

The connector to the board should be 4 pins, as should one of the fans be?
The second doesn't matter, as via the splitter, it's controlled by the primary fan.

33's have a zero RPM mode, which will generate a warning if they're zero upon boot. With that cooler and zero RPM functionality, disabling the warning is the only option.

Sorry for taking so long to reply.

So, in the CPU Q-Fan configuration in BIOS, I can change the CPU Q-Fan control to “Disabled” (default option is PWM Mode).

At first, it solved the problem, but now my friend is getting random boot screens with the “CPU fan error” message. The only option is to go to BIOS and change those settings again. The problem is that most times, even if it is set to “Disabled”, the computer won’t go past that boot error screen.

Is there any other option that should be tinkered with? He’s got the latest BIOS update.

Thanks,

Vasco Martins

EDIT: the connector from the fan to the motherboard is indeed 4-pin, I was confusing with the one that connects one fan to another, which only has 3-pins.

 

[Karadjgne]

The Arctic 33plus comes with wiring splitters enabling upto 3 fans (its a 2 fan cooler, so not sure why that's there). But you can daisy chain them. Just have to make sure you got the right section of chain. Not only must the pins to the mobo be a 4 pin connector, but also have 4 wires, and the other connector will have 3 wires in a 4 pin connection. The fans should be the F12 PWM.

 

[vasco.martins.drummer]

The Arctic 33plus comes with wiring splitters enabling upto 3 fans (its a 2 fan cooler, so not sure why that's there). But you can daisy chain them. Just have to make sure you got the right section of chain. Not only must the pins to the mobo be a 4 pin connector, but also have 4 wires, and the other connector will have 3 wires in a 4 pin connection. The fans should be the F12 PWM.

That’s not the problem. I was just unsure about the connections, but everything is at it should be.

The problem is that the MB insists on saying there’s a CPU fan error, even though the smart control is disabled. Both fans start on boot, so the motherboard shouldn’t read it as zero RPM.

 

[Karadjgne]

Can you try swapping the connection, use the rear exhaust fan in the cpu_fan header. See if it still reads 0 rpm at boot. Then try both the Arctic fans individually in cpu_fan header, without the splitter.

If you get 0 rpm for all 3, then you have a motherboard issue with that header, because there's no way all 3 fans will read 0 rpm direct connect. And you already know the exhaust fan is good as it's registering a speed.

There is supposed to be 2 parts to that splitter chain, only 1 part will have 4 wires. One of those fans must be connected to a 4 wire split, the others (fans 2 + 3) will be on a 3 wire, regardless of actual pin connection being 4pin or 3pin. Wondering if there's not something wrong with the splitter itself not allowing the speed sense (3rd wire) to make a connection. Not sure.

 

[Paperdoc]

If I understand the diagrams for that cooler system, the fan Splitter really is built into the wiring of the first of its two fans. That fan has a cable with four holes that plugs into the mobo CPU_FAN header, and ONLY that fan is supposed to feed its speed signal to the mobo header. Then that cable has a branch off that provides a second male fan connector, but with one of the four pins missing. The second fan plugs in there, and this arrangement ensures that the CPU_FAN header receives a speed spulse signal only from the first fan, exactly as it should work.

IF the wires or connector from the first fan is faulty, OR if the connection to the header has a poor connection from dirt or oxidation, it may fail to feed its speed signal to the header, and that would cause this problem. Alternatively, if the header itself has a flaw, the testing that Karadjgne proposes above will expose that. So, do those tests and narrow down which component is failing to get the speed signal to the header.

Many mobos (apparently including yours) monitor the speed of theCPU cooler carefully for FAILURE (i.e., no speed signal) and, if that happens, send out a warning which you are seeing. More than that, many will take pre-emptive action to prevent CPU overheating caused by a failed CPU cooler, and refuse to let you boot up if that fan does not show a speed. That is why your friend cannot boot. It's a direct result of not having a speed signal reaching the CPU_FAN header.

 

[vasco.martins.drummer]

Hello guys!

Sorry for taking so long to reply, but for some reason I didn’t get the notifications on the email.

So the motherboard has always read fan speed on the cpu:

https://imgur.com/a/dq9mHq8

View: https://m.imgur.com/gallery/dq9mHq8


The problem he keeps having is that even with that smart system disabled, the motherboard insists on giving an error.

Is this somehow a fail proof system for the motherboard, or an actual error with it?

The computer works just fine besides that.

Thanks,

Vasco Martins

 

[Paperdoc]

If the mobo gives a fan failure warning for the CPU and refuses to allow booting up, then the CPU_FAN header is NOT receiving a fan speed signal. That, or the mobo CPU_FAN header itself has a major flaw. NOTE that monitoring the CPU cooler fans (or whatever is plugged into that header) for FAILURE is separate from the QFan control system, so normally turning QFan off will NOT stop the process of monitoring the header for fan FAILURE.

Before going further, let me suggest you use a different tool for some of these checks. Use BIOS Setup screens to get to the QFan configuration screens - see your manual, p. 2-1 and 2-2. Those WILL show you reliable readings of fan speeds as detected by the mobo.

So, why does the CPU_FAN header believe its fan is NOT working? Well, a flaw in the header is one way. NOT plugging ANYTHING into the CPU_FAN header is another. If there is ONE fan plugged into that header, it MAY actually not be turning, but you say that is not the situation. Or, it may have a bad connection of its fan speed signal line to the header - that is Pin #3 of the header. Karadjne above suggested testing for thus: try plugging into that CPU_FAN header some OTHER fan to see if the "fan failure" warning goes away, because it is unlikely that several fans all would have that same flaw. If the error persists, that says the problem is in the header itself.

If you have two or more fans connected to that CPU_FAN header using a Splitter or a Hub, then we look at other items. With the Arctic Freezer 33 Plus system you have, the two fans for the CPU cooler have wiring that connects both of them to the single CPU_FAN header, and that wiring system effectively is a simple Splitter. It just connects all the fans together in parallel to that header. EXCEPT that, for the fan speed line on Pin #3, only the speed signal from the FIRST fan is sent back to the header; the other(s) are ignored, and that is done by omitting Pin #3 on the male connectors to the "other" fan(s). With that system, IF the speed signal from the FIRST fan is faulty it will not get to the mobo header and that could cause this issue. If you did the tests above suggested by Karadjne and all the "other" fans you use DID eliminate the error problem, then the trouble IS in the one fan (the FIRST of the Arctic Freezer set), and there is a work-around I can suggest. If that is your situation, next test is to plug the SECOND of the Arctic Freezer fans directly into the CPU_FAN header and temporarily NOT plug in the FIRST of those fans. IF this arrangement also eliminates the error messages and allows booting, then you know you can make this next idea work. For that, get a simple 2-output, 4-pin SPLITTER like this

https://www.newegg.com/p/N82E168124...r&cm_re=coboc_splitter-_-12-423-160-_-Product

Plug that into the CPU_FAN header, then plug into its one output that HAS all four pins the connector from the SECOND Arctic Freezer fan - that is, the one you know DOES send back a good speed signal. Then plug into the other output the cable from the FIRST Arctic Freezer fan that cannot send back a good speed signal, because that missing signal will never be looked at, anyway!

Now, if NONE of those tests seem to work and eliminate your problem, there's another possibility IF you do have non-zero speed shown for the CPU_FAN header. SOME mobos have a way for you to specify the exact minimum speed a header will accept for a good fan. This is the lower limit of aceptable fan speed, and any slower fan may be interpreted as having failed. You mobo manual does NOT indicate that you have any option to change this - it may be a fixed setting. So if you cannot change it, there's another possibility IF it does show that the fan HAS a speed that is not zero. Within the QFan configuration tools you may find an option to change the Fan Profile from the default to using your own custom fan speed "curve". It's often a simple graph of what fan speed is to be set for a given measured temperature. You can force a higher minimum fan speed by changing the speed settings on this curve for the two lowest temperatures to higher speeds, so the fan never goes too slow when the system is cool.

Some of this depends on being able to boot into BIOS Setup in the first place so you can see some info and make changes. If that is not possible even when you change to different fans plugged into the CPU_FAN header (because the system refuses to let you boot anything at all), that's a different problem. That probably gets us back to a failure of the header itself. That is, if NO fan plugged into the CPU_FAN header appears to deliver a good speed signal even though you can see the fan IS turning, and hence you cannot boot, you will need to talk to Tech Support from ASUS about an apparent mobo failure.