NG4 (Citroën C5 X7) Date does not change to next day, time works correctly

[Borsh]

Hello everyone,
I’m looking for help with a strange issue on an NG4 head unit (Citroën C5 X7).

Problem description:
-Time (hours/minutes) runs correctly.
-Date can be set manually and is saved correctly.
-However, the date does NOT change to the next day at midnight – it stays stuck on the same day indefinitely.
-The clock continues to run normally.


What I have already tested:

-GPS time synchronization ON and OFF – no difference. Time continues to run in both cases but date is stuck.
-Date is remembered after ignition off / battery disconnect.
-Settings are saved correctly.
-No CAN or BSI errors reported.
-I tested several different NG4 firmware versions.
-I performed BSI resets and battery disconnect procedures.
-I replaced the original HDD with a CompactFlash card (CF mod) – the issue remains exactly the same.

Important additional information:

-I also tested another complete, used but nower 2010 NG4 head unit – the problem was identical.
-I also tested another BSI together with engine ECU and instrument cluster - no change.

Pleas Help

[mickthemaverick]

I'm not familiar with that system but is there an option in settings to turn on/off daylight saving times?

[Kees]

I have the same unit and just checked it for you and saw, this date today: 17-11-2025.
So went to the setup to change, gps sync was on, change the date and go back to the main nav screen.
The date went back to 17-11- 2025.
Now I go back to the setup, change GPS sync to off, and now this is important! after you switch GPS sync off GO BACK to the main nav screen and check if the date is still correct, if yes then you can the GPS sync back on and it will be oke and keep the correct time and date.
Greetings,
Kees.

[Kees]

https://www.manualslib.com/download/107 ... g4-3d.html

Here you find the complete manual.

[Borsh]

I have the same unit and just checked it for you and saw, this date today: 17-11-2025.
So went to the setup to change, gps sync was on, change the date and go back to the main nav screen.
The date went back to 17-11- 2025.
Now I go back to the setup, change GPS sync to off, and now this is important! after you switch GPS sync off GO BACK to the main nav screen and check if the date is still correct, if yes then you can the GPS sync back on and it will be oke and keep the correct time and date.
Greetings,
Kees.

Date can't be change when GPS sync is on.
It looks like you’re also experiencing an issue with the date getting stuck. Tomorrow, you’ll see today’s date, which will be incorrect.

[Kees]

You see, it keeps the date correct!

Maybe you forgot if you change the date, then you have to go to the time as you see in this picture, because otherwise the date is not saved before you do this.

[Borsh]

But today is 22 dec not 21 dec.
The problem is that the date does not change with the days, manual change and saving is not a problem. When I change the date manualy I do this by silmply click OK with the main dial to save it.

[Kees]

Sorry, my mistake, i think i was a bit of sleeping, but the date changed overnight!
Maybe it's better for you to make a reset, by pressing the number 1,3 and 5 simultaneously until you hear a beep.

[Kees]

I think, you have the wrong expectation about the system.
It doesn't synchronizes the clock/date with the GPS signal!!
It only use the GPS voor the navigation route, to tell you at what time you arrive and if there is any road block/accident.
Just try it by yourself, put a wrong time in the system, then make a trip with the car to see if the time change to the correct one.

[Borsh]

From what I’ve noticed, GPS synchronization only ensures that the set time does not drift over time. I did not expect GPS synchronization to set for me correct date and time.
However, whether GPS synchronization is enabled or disabled, the problem is the same: the date does not change overnight to the next day.
This is a problem that has started occurring for a large number of users, and so far no one seems to know a solution.
I have tested all possible reset options: using every available button combination, as well as resets from the standard settings menu and the hidden settings menu 123 with no results.

[Kees]

Maybe you have to look in a different direction, see this post:
viewtopic.php?p=830826#p830826
In the past I replaced the RT4 for the NG4. For this reason i don't have this module in my car and therefore switch this of with the diagbox.

[Borsh]

I'll check it out, but I don't think it will help. Do you remember the path in DiagBox where to disable it? It was in BSI?

[Kees]

I will look for it tomorrow

[Kees]

You go to repair/NG4/options costumer/manual telecodering/servicemodule

[Kees]

Today I find out something, I put around 11 o'clock this morning the system on 23:55 with the date on 22-12-2025 and GPS sync off, keep the engine running.
At 00:00 the date changed from 22 to 23-12-2025.
So the problem is that when you parked the car overnight, the eco-mode kicks in and if the battery from the service module is bad, this is te reason for the problem.
Because I don't have this module in my car i have to find out how the battery from this module is connected to the NG4.