Asus Maximus Z790 Extreme stuck on Q-Code 16 error on boot up

[LiLAsN]

My setup:
CPU: Core i9-13900K
Motherboard: Asus ROG Maximus X790 Extreme
RAM: Kingston Fury Renegade 6400MHz CL32 (2 X 16GB)
Graphics: Asus ROG Strix RTX 4090

Hi.

I am having an issue where I am constantly getting this Q-Code Error 16 being displayed with the small motherboard screen saying 'Check CPU' while in the manual, it says that 15-18 has something to do with "Pre-memory System Agent initialization is started".
What I have done is reseating the CPU.
I have also tried to use just 1 stick of RAM each time at the appropriate second RAM Slot. Tried to switch around both RAMs on the 2nd and 4th slot.
I have unplugged and replug the 24-pin. And the CPU 8-pin on the top left including double checking my PSU connections.
I went from the official stock BIOS to the latest 0703 BIOS on the board too and still no change.
Cleared CMOS.
I tried all 4 combinations of "MRC Fast Boot" and "MCH Full Check", Enabled-Enabled, Disabled-Disabled, Enabled-Disabled, Disabled-Enabled. And all 4 changes nothing to this error occurring sadly.

How this error occurs is upon a boot up after a shutdown or a restart. I cannot start the PC a second time when there's power. It must be from no power and then for some reason, it will not have that error and I can boot straight into my Windows and run it without issues. The problem is, with a new hardware, drivers and even my Nvidia drivers need to be reinstalled which requires a restart. Once, the restart happened after an Nvidia driver install and I was stuck in the Code 16 error forcing me to turn off the power supply cutting off the power. Upon boot up, when it is supposed to reach the Windows login screen, the screen goes black as a result of a bad install due to having to shut off the power because of the Code 16 error. I managed to solve this by using DDU in Safe Mode and reinstalled the drivers on Windows successfully but not being able to restart due to the motherboard error is stopping me from getting my Windows up and running.I also ran the CPU and RAM at the stock Auto settings in the UEFI BIOS. Running at stock Intel standards for the CPU and RAM at the Intel speeds instead of XMP. Even running XMP doesn't change anything. MCE on or off makes no difference too. Am currently running the system using Derbauer's 70W efficiency. I have played games as a stress test and use my PC as per normal with no issues. It is only when the PC is restarting or booting up a second time with power not being cut beforehand, that this issue will occur.

Here's a reddit of a couple of people with the same issue on their system.
https://www.reddit.com/r/ASUSROG/comments/yahbn4/code_16_check_cpu_help/

Any help would be appreciated. Thanks!

[STARRAIN_ROG]

Hi LiLAsN,
Does it show Q-Code Error 16 and no video output after restart every time and you have to switch PSU off and on to get the video output? or it is no boot when get Q-Code Error 16?
If you just shutdown the pc and turn it on again, does it still show Q-Code Error 16?
Does it occur since first build?

May I know where you downloaded bios 0703?
Is your ram model in our QVL list?
https://rog.asus.com/motherboards/rog-maximus/rog-maximus-z790-extreme-model/helpdesk_qvl_memory/
When it show Q-Code Error 16, which Q-LED on the motherboard is lit? (CPU [red], DRAM [yellow], VGA [white], Boot Device [yellow green]
If the issue also occurs with bios all default settings(no OC), please enable CSM in bios to see whether it still persists.

Thank you.

[LiLAsN]

STARRAIN@ROG wrote:
Hi LiLAsN,
Does it show Q-Code Error 16 and no video output after restart every time and you have to switch PSU off and on to get the video output? or it is no boot when get Q-Code Error 16?
If you just shutdown the pc and turn it on again, does it still show Q-Code Error 16?
Does it occur since first build?

May I know where you downloaded bios 0703?
Is your ram model in our QVL list?
https://rog.asus.com/motherboards/rog-maximus/rog-maximus-z790-extreme-model/helpdesk_qvl_memory/
When it show Q-Code Error 16, which Q-LED on the motherboard is lit? (CPU [red], DRAM [yellow], VGA [white], Boot Device [yellow green]
If the issue also occurs with bios all default settings(no OC), please enable CSM in bios to see whether it still persists.

Thank you.

Yes, it will show Q-Code Error 16 and no video output after restart every time. It won't even show the BIOS Splash screen as it is running the tests before it shows the BIOS splash screen. And yes, I'll have to switch PSU off and on to get the video output.
If I just shutdown the pc and turn it on again without cutting off the power first, then yes, it will still show Q-Code Error 16.
Yes, it occurred since first build and now, even on the latest 0801 BIOS FW.

I got the BIOS from
https://rog.asus.com/forum/showthread.php?131027-RaptorLake-Resources
and clicking on Z790 Extreme.

Yes, my RAM is in the QVL list. Kingston Fury Renegade 6400MHz CL32. Part no. listed as KF564C32RSK2-32 in the list.

When the Q-Code 16 error occurs, unfortunately, none of the LEDs next to the Q-Code are lit up. Not the red, white or yellow lights. Nothing.

I've tried enabling CSM which results in the weird aspect ratio. Upon restarting, again the BIOS initialization phase, it will still get stuck at Q-Code 16 error. Weirdly enough, on the 1st boot when just receiving power, I do see it cycling through Code 16 but never got stuck there. It is only when restarting or booting up from standby that this error occurs.

As for my Windows 10 experience. There are no errors to speak of. Everything just works. Played A Plague's Tale 1 and 2 along with God of War. No errors to speak of.

Is there anything else that I can do. My distributor here doesn't have any spare Z790 Extreme motherboards to exchange with. And having to send back the motherboard to Asus directly will take 30 days without me having a spare motherboard being given by my distributor to use in the mean time. I desperately need your help. Looking forward to your reply. Thank you.

[STARRAIN_ROG]

Hi LiLAsN,
Do you mean get stuck at Q-Code 16 error even after switch PSU off and on with CMS enabled?
Please update Intel ME Version 16.1.25.2020 from our support site.
Do you have another CPU, graphics card and PSU to cross check?
Thank you.

[LiLAsN]

STARRAIN@ROG wrote:
Hi LiLAsN,
Do you mean get stuck at Q-Code 16 error even after switch PSU off and on with CMS enabled?
Please update Intel ME Version 16.1.25.2020 from our support site.
Do you have another CPU, graphics card and PSU to cross check?
Thank you.

No. Once the PSU is turned off, the issue goes away. It is only when the system shuts down or reboots while it is still receiving power. Basically, on the 2nd boot or initialization of the motherboard. This includes when you make any changes to the BIOS and the motherboard has to rerun the initialization sequence again. That is when I'll be stuck in this boot too.

Yes! I just updated to Intel ME Version 16.1.25.2020 yesterday. Even the new Asus ROG Strix RTX 4090 v2 BIOS that just came out as well. No changes on this issue.

That's the sad part. Since my last platform was the i9-9900K, I unfortunately do not have a spare CPU to test on. As for GPU, I still have my RTX 3090 and a spare PSU. But as we have determined, this issue is solely on the CPU or motherboard.

[STARRAIN_ROG]

Hi LiLAsN,
Looks like the result with CMS enabled is same as bios defaults?
If you have another ram in the QVL list, and another compatible GPU & PSU, could you please help to cross check if the issue still there with them?

May I have the following information?
- the serial numbers of your motherboard and GPU via pm
- the brand and the model name of OS drive, PSU and monitor(with HDMI or DP)
- graphics driver version
- vbios screenshot in GPU TWEAK like the screenshot below

- OS version and OS build
- a video of the Q-Code 16 issue
Thank you.

[PhilOlea]

Same thing here can hard boot fine, gets stuck on 16 after a soft boot 😞