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System Fan (90B) error on fanless laptop

HP 250 G4 Notebook PC
Microsoft Windows 7 (64-bit)

System Fan (90B) error on fanless system!

 ‎04-18-2018 08:33 PM - edited ‎04-18-2018 08:53 PM

Product: HP 250 G4 Notebook PC

Operating System: Microsoft Windows 7(64-Bit)


My laptop goes to an error as soon as I turn it on. The error reads:


Continued operation is not recommended and may cause unpredictable behavior that could result in random shutdown, data loss or possible system damage. The system will shutdown in 15 seconds. To prevent shutdown and continue operation, press the Enter key now.


The system has detected that a cooling fan is not operating properly.

System Fan Error (90B)


ENTER - Continue Startup


For more information, please visit:


This laptop was designed  like the passively cooled... with no fan.


 There is no fan to function properly nor improperly!


I have cleaned and replaced the Heatsink Thermal Compound

no change

I have replaced AC adapter for new one. (old 19.75V  new 19.4V)

no change

I have run the battery test by pressing F12 (PC Hardware Diagnostics UEFI Window)

no change

I have updated the BIOS from F.1E to F.1F

no change


I still got the error message.


I accessed the BIOS Setup Utility and loaded and saved the default settings.

no change

I have "dried out the cmos" by removing the power supply connection, the main battery and the onboard RTC battery. I held the power button for a minute.

no change

I have left the RTC battery out to "dry out" the cmos overnight. (old school)

no change


I have done everything and read  every topic about System Fan Error (90B) but I still have error message on boot.


Does anyone know how laptop generate that message and where it stored?

Does temperature sensor that detect error may be nonfunktion?

There is no Temperature alarm setup in BIOS.





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