Resolved Mac Pro 6,1 (2013) - fan runs at 100%

[Spacedust]

I’ve started Far Cry 3: Blood Dragon under Windows 8.1 and after a few seconds fans went to the max, but it was still working.

Then suddenly screen went black. Post reboot everything was back to normal but fan was running at 100%.

Nothing is overheating CPU, GPU's or SSD's.

I can still control the fan with Macs Fan Control, but on auto it always goes to 100%.

Apple diagnostic shows PPN001 and PFM006 – issues with SMC and power management system.

I’ve tried NVRAM RAM reset and unplugging from the socket for a whole, but doesn’t help.

Where is the SMC chip location in this machine on the CPU board or the bottom board ?

 

[Spacedust]

Looks like second GPU 2 - Die sensor is gone

 

[Spacedust]

Seems both GPU's are working well under Windows - FurMark showed Crossfire working and both gets proper temperature readings.

 

[Spacedust]

I've removed one GPU (the one with SSD slot), then reinserted it. GPU2 die sensor reappeared. LuxMark shows both GPU's core clock 850 MHz (previously first GPU showed just 150 MHz). Fan is now working properly. Apple diagnostic shows no issues at all.

 

[Spacedust]

It ended up one GPU repair as well as SMC repair. Cost about $639.