Solved: Re: How to disable/fix 90b System Fan error on boot - HP Support Community

ChuckCB1 · ‎03-22-2026

Hello! I have an HP Spectre x360. A had to replace the CPU/GPU fans. When booting up, I get 90B System Fan error and that system will shutdown in 15 seconds.

So, I 'Enabled' Fan Always On setting in BIOS. Fan runs without issue and seems to throttle when needed.

I want to test again with Fan Always On 'Disabled' (factory) to see actual behavior.

But, question is, it seems this error happens with non-OEM replacement fans? If so, is there any way to disable this error?

Thanks!

VikramTheGreat · ‎03-24-2026

Hi @ChuckCB1,

Welcome to the HP Support Community.

Thank you for posting your query. I will be glad to help you.

The 90B System Fan error typically indicates that the system fan is not operating correctly, which can be a critical issue as the fan helps in cooling the CPU/GPU, preventing overheating. When this error occurs, it's usually due to the fan not being detected or functioning properly.

Please check the following:

Make sure the laptop is placed on a flat, hard surface (avoid beds, cushions, or laps)
Check that the air vents are not blocked on the sides or bottom
Inspect the vents for dust or debris, and gently clean them using compressed air if available

Basic troubleshooting steps:

Turn OFF the laptop and disconnect the charger
Hold the Power button for 15 seconds to reset the hardware
Turn the system back ON and check if the error persists

Additional checks:

Ensure the replacement fan is properly connected and seated correctly
If possible, re-open the unit and verify there are no loose connections
Enter BIOS (F10 at startup) and check if the system detects the fan properly

Important note:

If the vents are clear, the system is on a proper surface, and the issue still continues, this may be due to fan compatibility or sensor detection, especially with non-original parts.

If you continue to see the error after these checks, please let us know your exact model number so we can guide you further.

I hope this helps.

Take care and have an amazing day!

I'm an HP Employee.

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View solution in original post

VikramTheGreat · ‎03-24-2026

Hi @ChuckCB1,

Welcome to the HP Support Community.

Thank you for posting your query. I will be glad to help you.

The 90B System Fan error typically indicates that the system fan is not operating correctly, which can be a critical issue as the fan helps in cooling the CPU/GPU, preventing overheating. When this error occurs, it's usually due to the fan not being detected or functioning properly.

Please check the following:

Make sure the laptop is placed on a flat, hard surface (avoid beds, cushions, or laps)
Check that the air vents are not blocked on the sides or bottom
Inspect the vents for dust or debris, and gently clean them using compressed air if available

Basic troubleshooting steps:

Turn OFF the laptop and disconnect the charger
Hold the Power button for 15 seconds to reset the hardware
Turn the system back ON and check if the error persists

Additional checks:

Ensure the replacement fan is properly connected and seated correctly
If possible, re-open the unit and verify there are no loose connections
Enter BIOS (F10 at startup) and check if the system detects the fan properly

Important note:

If the vents are clear, the system is on a proper surface, and the issue still continues, this may be due to fan compatibility or sensor detection, especially with non-original parts.

If you continue to see the error after these checks, please let us know your exact model number so we can guide you further.

I hope this helps.

Take care and have an amazing day!

I'm an HP Employee.

If this reply helped resolve your issue, please select the Accept as Solution as it helps others in the community quickly find the answer they’re looking for.

And if you found this reply helpful, clicking Yes below is a great way to let us know we’re providing the support you need, as it encourages us to keep improving and sharing helpful guidance.

ChuckCB1 · ‎03-25-2026

Thanks Vikram! After this post, I reseated the fan cables and the error went away and laptop is running cool again.

Thanks!

VikramTheGreat · ‎03-25-2026

Hi @ChuckCB1,

Thank you for the update. Glad to hear that reseating the fan cables resolved the issue, and your laptop is running normally again.

Please reach out to us again if you need any help, and we’ll be happy to assist further.

Take care and have a great day ahead

I'm an HP Employee.

If this reply helped resolve your issue, please select the Accept as Solution as it helps others in the community quickly find the answer they’re looking for.

And if you found this reply helpful, clicking Yes below is a great way to let us know we’re providing the support you need, as it encourages us to keep improving and sharing helpful guidance.

How to disable/fix 90b System Fan error on boot

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