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Rimmsi

macrumors regular
Original poster
Jun 19, 2021
172
65
Czech Republic
Hi, I recently bought a used Mac Pro 7.1 on ebay. Everything seems to work as it should, the machine is incredibly quiet and cool and looks like new. I just replaced the w5700x module with an RX 6900 XT. This afternoon out of curiosity I ran the device diagnostics and after the test finished I got the error code PPF004 which means the fan has failed. Using the iStat menus, I manually tested all the fans and got to the maximum speed (blower 1406rpm, front fans 2740rpm). Emotionally, it seems to me that everything is fine and nothing squeaks or makes a bad sound. Has anyone encountered a similar situation on their MP 7.1? Thank you.
 

DeltaMac

macrumors G5
Jul 30, 2003
13,486
4,413
Delaware
That PPF004 does NOT mean "the fan has failed".
PPF004 actually means that "there may be an issue with the fan"
You have checked the fans, and I think you do not agree the fan has failed.
If you used a utility, such as Macs Fan Control, or smcFanControl, to test the fans from idle to full speed, then back to idle and no problem found, then the error that you see may be just a "false positive" that you can probably choose to ignore.

Be sure to try an NVRAM reset, if you have not already tried that.
Just curious - Does that hardware test pass if you use the old W5770X, instead of the RX6900XT?
 

Rimmsi

macrumors regular
Original poster
Jun 19, 2021
172
65
Czech Republic
I tried only test with the RX 6900 XT. Even after resetting the NVRAM I still get the PPF004 error code. I can try it when I have time.
 

Rimmsi

macrumors regular
Original poster
Jun 19, 2021
172
65
Czech Republic
So I swapped graphics card back to the W5700X and the test completed without error. Oh, I was really worried it was going to be something more serious. Thank you for your help.
 

CurtisBilly

macrumors member
Nov 1, 2006
45
27
I also have a Mac Pro 7,1 and RX 6900 XT. The internet brought me here after I ran Apple Diagnostics and found a possible issue with my fan.

With my RX 6900 XT connected to the display, Apple Diagnostics on my machine gives the same reference code as OP: PPF004 "There may be an issue with the fan".

This thread was very helpful to me. So I am sharing further debugging findings that I learned from multiple runs of Apple Diagnostics:
  • With only a 580X MPX Module installed Apple Diagnostics yields ADP000 (No issue found).
  • With only a RX 6900 XT installed Apple Diagnostics yields PPF004 related to a possible fan issue.
  • With both graphics cards installed and the RX 6900 XT connected directly to a display Apple Diagnostics yields PPF004 related to a possible fan issue.
  • With both graphics cards installed and the 580X MPX Module connected directly to a display Apple Diagnostics yields ADP000 (No issues found). Hooray!
This was driving me nuts, because I recently changed both my monitor and reconfigured my Mac Pro. Specifically, just the other day I removed the 580X MPX Module after swapping out to a new monitor from an old Apple Thunderbolt Display. I was positive I was previously getting ADP000 (No Issue found) with both the RX 6900 XT and 580X MPX installed. I was only keeping the 580X MPX Module installed to drive the Thunderbolt Display.

The last debugging step above finally proves to me what is going on; that there is no issue with my Mac Pro and perhaps Apple Diagnostic's PPF004 false positive comes from having a non-MPX graphics card driving the display.
 
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