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Paper Tape
Posts: 6
Registered: ‎02-09-2012
Location: Somerville, MA, USA
Views: 1,468
Message 1 of 4

T400s fan error

Hi all,


a few days ago, when I tried to boot my T400s, I got a "fan error" message.


The fan starts up the moment I press the power button and then abruptly turns itself off after a few seconds.


No start up.


I thought: "fine, I need a new fan", ordered one, installed it without any problems according to the hardware manual (including diligently applying thermal grease).


When I tried to start again, exact same situation.


I can force my computer to start up by pressing ESC when the fan error message appears and it will boot, but the fan is making rather strange noises, namely starting up and shutting down immediately, and starting again and shutting down again [indefinite loop]. I don't like it!


The fan replacement did not do anything for me and I don't have warranty any more. Any thoughts? Is this a BIOS problem maybe? I don't really know what I am doing here. Smiley Happy Would appreciate any suggestions!


Thanks much!

Community SeniorMod
Community SeniorMod
Posts: 8,990
Registered: ‎01-01-2010
Location: US
Views: 1,463
Message 2 of 4

Re: T400s fan error

It is hard to diagnose from 3000 miles away, but it sounds to me like the circuitry on the motherboard that counts the tach pulses from the fan has died. If it were mine, there is one thing I would try.  I would reset everything. Make sure you have cleared supervisor (bios) and power-on passwords first. Pull the AC adapter and battery. Disconnect the CMOS battery. (note that this will cause you to lose your date and time, and any changes you made to default BIOS settings. I don't remember about that model, but you may lose stored fingerprints) With no power and no cmos battery, push the power button a few times and hold it for 5 seconds. Put it back together and pray.


I do not respond to requests for private, one-on-one help. Your questions should be posted in the appropriate forum where they may help others as well.

If a response answers your question, please mark it as the accepted solution.

I am not an employee or agent of Lenovo.
Paper Tape
Posts: 6
Registered: ‎02-09-2012
Location: Somerville, MA, USA
Views: 1,457
Message 3 of 4

Re: T400s fan error

Thanks so much. I am praying, but on a more practical note, I am not sure where to find the CMOS battery. Lots of googling did not really help. Can you please give a hint?


Thanks again

Community Moderator
Community Moderator
Posts: 1,320
Registered: ‎12-19-2011
Location: MY
Views: 1,444
Message 4 of 4

Re: T400s fan error

Try going through the HMM for the T400s.

I did provide you with the exact page in the HMM for the CMOS batt however the free wifi I am using is too slow =(

*Non Lenovo employee*

I have a Y530 ... Feel free to highlight any post which you have posted on the forum to me if no one have chimed in.

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