The HP 600 g2 mini has 901 rear fan error on 65w cpu's

[G_man777]

PC boots with 901 rear fan error whenever a 65w cpu is installed. I upgraded i5 6500t to i5 6500 and the system  boots with 901 fan error every time. Keep in mind that only 90w power supply or above is needed for 65w cpu's. How can I fix this error as the cpu is supported on the 600 g2 mini. Please help.

[BeemerBiker]

Did you use the 65 watt cooler for the CPU?  Very likely, the bios is checking the fan to see if the correct fan was installed.

I found the above by first looking here

https://partsurfer.hp.com/partsurfer/?searchtext=HP%20ProDesk%20600%20G2

and then picking a product ID that has the 65 watt CPU and looking for the cooler

Can you take a picture of the connector the fan is plugged into?  If it has an extra unused pin then it may be possible to fool the system into thinking the better fan is attrached.

The warning message you mentioned was the rear fan.  Maybe the problem is the rear fan cable is bad?

Possibly our expert @Paul_Tikkanen might be able to help with a better fix.

[Paul_Tikkanen · Accepted solution]

Hi:

Below is the link to the HP Quickspecs for the Prodesk 600 G2 PC model series.

HP ProDesk and ProOne 600 G2 Business PC Series QuickSpecs (cnetcontent.com)

The list of supported processors by form factor can be found on pages 10 - 12.

Only the processors that end in a 'T' are supported in the 600 G2 DM.

That is why the i5-6500 is throwing a 901 rear fan error.

There is no fix that I know of other than to reinstall the i5-6500T.

If you want, you can upgrade to the i7-6700T.

[G_man777]

Thanks for the suggestions @BeemerBiker

Unfortunately, this motherboard doesn't have a physical rear fan connector on the board itself.

so will have to go with Pauls solution

[G_man777]

Thanks @ Paul_Tikkanen

This seems to be the only solution. Only using this device as a micro server so the T series CPU's should be sufficient.

Thanks again

[Paul_Tikkanen]

You're very welcome.

[BeemerBiker]

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@G_man777 wrote:

Thanks for the suggestions @BeemerBiker

Unfortunately, this motherboard doesn't have a physical rear fan connector on the board itself.

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I had thought the same thought,  that the bios is actually reporting the CPU fan is not the correct fan for the system but gave the back fan as the problem.

I have had several z400 motherboard and all complained or would not boot unless the original fan was on the CPU. A jumper to ground from one of the fan pins allows booting without pressing F1.  There was also a wiring change to the 24 pin connector that was needed for my Z400s.

However, the 4 core 8 thread low power recommended by @Paul_Tikkanen is better than that CPU you obtained.  I still think the bios can be fooled into allowing a boot with some type of fan trick.

[Tomppa81]

I have similar problem.

Do you happen to know, that what pin of the fan needs to be connected to ground to be able to boot without pressing F1 ?

I wouldnt want to try it without knowing what wire to try 🙂

[BeemerBiker]

I was guessing based on my experience with a Z400 motherboard where I had to press F1 to continue.

This is the explanation of how to fool the Z400 quote

The Z400 performance heatsink/fan is HP part 463981-001, and its fan is a Delta AFB0912HH, with standard 4 wire PWM in/out of the motor.  The 5th hole in the plug would be empty if it was a mainstream heatsink/fan, and is occupied with a ground jumper from hole 1 to 5 if it is a performance heatsink/fan.  That is how the motherboard knows a performance fan is attached.  It can't tell by current or rpms what is going on..... 

I have no idea if this will work on your system. Is there a 5 pin socket for the fan with one pin unused?    if not it wont work

Actual article is here

https://h30434.www3.hp.com/t5/Business-PCs-Workstations-and-Point-of-Sale-Systems/Z400-heatsink-fan-...