Yes, the error log of DM5 actually gives a hint: “External pressure sensor raw pressure out of rang”, you can find the error log under C:\Users<username>\AppData\Roaming\Suunto\Suunto DM5<DM5 Version>\error.txt
EON Error 16
Device: EON Core
Serial: xxxxxxxxxxx
HW Version: F.3.0
SW Version: 3.0.1102
Error Code: d1c00600
ms5541-30c.cpp line 479
External pressure sensor raw pressure out of rang
Last thread: Tas
Last task: Del
Last delegate: Ms5
7.10.2024 7:08:15
PSP: 0x2000D958, MSP: 0x2001FFE0
INT FLAGS0: 0x0, INT FLAGS1: 0x0
GPIO FLAGS: 0x0
BASEPRIO INT: 0x1
CPSR INT: 0x1
EXCEPTION FLAGS: 0x0
IRQ FLAGS: 0x0
IDLE: 0x0
MISSED SYSTICKS: 0
SCHEDULER SUSPENDED: 0
(And yes, all 16 errors in that log are the same error code and reason, just different dates)
So basically it means that the reading from the pressure sensor is not in range.
Interestingly enough, soaking the core in fresh water for a few minutes and then rebooting makes the error go away for me. (Possibly, because this moves the pressure sensor a bit, generating new data)
Another time, I was able to fix it by simply connecting it to an older version of DM5 which then proceeded to downgrade the computer to firmware 2.xx, but I do not have that version of DM5 anymore.
The computer does work fine after these fixes (with reference to my D5 that I wear on my other arm), but be careful with this and only use these approaches as a quick fix if you are on a boat or vacation where you do not have the option to easily send the computer in, and send the computer in immediately after you return home.
This error only ever comes up for me when I am on vacation (so in salt instead of fresh water and higher surface pressure level) and always when charging, so likely fluctuations in the power supply from unstable outlets cause this. Do not trust boat/hotel power outlets to be stable.
Since I first got this error, I usually put a power bank between the dive computer and power supply as a buffer, but I forgot to bring one this time again. My D5 charging on the same charger at the same time does not have this issue.
But try these ideas only as a quick fix if you are on a boat or vacation where you do not have the option to easily send the computer in, but then send the computer in after you return home.