Fan Error 90B stopping your PC from starting? Let’s solve it.

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Troubleshooting Steps for System Fan Error 90B

The System Fan Error 90B indicates that your computer’s cooling fan isn't operating correctly, which may lead to overheating and potential damage.

Below are detailed troubleshooting steps to resolve this issue:

Symptoms

• Fan error 90B at boot
  
  
• The system may shut down unexpectedly, leading to potential data loss or system damage
  
  

Possible Causes

• Defective fan or loose fan connection
  
  
• The system fan is not spinning or not spinning properly
  
  
• The internal case temperature is too high, possibly due to obstructions blocking the fan's airflow
  
  
• Outdated BIOS
  
  

Troubleshooting Steps

1. Update BIOS and Drivers:
   
   

   • Ensure that the BIOS and drivers are up to date, as updates might include new fan characteristics and performance improvements for other components.
     
     
   • You can find the latest drivers on the HP support website by searching for your specific product model.
     
     
     

2. Perform a Hard Reset:
   
   

   • Turn off your computer and disconnect the power cord.
     
     
   • Remove the battery if applicable.
     
     
   • Press and hold the power button for about 15 seconds.
     
     
   • Reconnect the battery and power cord.
     
     
     

3. Verify Thermal Conditions:
   
   

   • Check the fan and its connection to ensure the cable is secure.
     
     
   • Inspect the heat sink fan, fin, and vent for dust or obstructions, and clean them if necessary.
     
     
   • Reseat the fan cable if it’s loose.
     
     
     

4. Test the Fan:
   
   

   • Use the HP PC Hardware Diagnostics tool (UEFI) to test if the fan is producing loud noise and that fan blades spin correctly.
     
     
   • Test with a verified working fan if possible.
     
     
   • If necessary, remove old thermal compound and replace it with new pads for better thermal management.
     
     
     

5. Verify Thermal Solution:
   
   

   • Use the Thermal Monitor tool (available to authorized service providers/technicians) to run stress tests and verify that thermal sensors are within limits after servicing the thermal condition.
     
     
     

6. Fan Replacement Verification:
   
   

   • If the fan is faulty, it might need replacement. Replace the fan and ensure it is tested with the HP PC Hardware Diagnostics tool.
     
     

Additional Notes

• Boot errors associated with System Fan Error are usually from previous boots where a fan error was detected. Therefore, addressing the hardware issues promptly will restore regular operations in subsequent restarts.
  
  
• Always ensure your computer is not placed on hot surfaces or environments that block proper airflow.
  
  

For more information, you may refer to the HP support resources HP PCs - 900, 901, 909, 90A, 90B, 90E, 90F, 911 error is displayed on a black screen

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