What will happen if i leave my car without a battery overnight?

[onix45]

Hello,

my C4's stop-start function stopped working recently. Upon checking with Lexia i noticed that my battery charge is below 75%.

So my question is, what will happen to the car if i take the battery inside to charge overnight? What functions (like radio, trip distances, etc) will reset to their default values? Anything i should be worried about?

[Paul-R]

Can you not charge the battery in the vehicle? That would be better.

You may need a new battery. Our 2015 308 had a battery fitted a couple of weeks ago (under warranty fortunately) as part of an investigation to get the start/stop working properly. That was also reading about 75% IIRC and repeated chargings up did not effect an improvement.

WRT to charging off the car I would wait for a couple of minutes after switching off or opening a door or anything that might wake the BSI up before removing the battery. The radio and trip will survive the experience.

[xantia_v6]

The only thing that should need resetting after replacing the battery is the time and date on the clock.

Ideally, you should follow the BSI reset procedure when disconnecting and reconnecting the battery (obviously doing the charging thing between the instructions for disconnecting and reconnecting).

[petef]

Our 2007 C4 reverts to French on the display when battery reconnected. Needs a delve into the menus to sort out, si vous n'êtes pas content.

[flying clutchman]

stop start not working strikes me as a bonus!

[Peter.N.]

Me too.

[Paul-R]

Decidedly not!

[Mike60]

Morning
About car battery.
If i change battery i need to introduce code for radio ?
Seller Citroen dealership told me i don't need it. BSI make this for me. But how ? I don't understand !
I found only this information :

" Resetting the BSI computer:
Open the drivers window and the bonnet.
Close all the doors, switch off everything, like the radio, phone charger etc.
Remove the ignition key via the open window
WAIT 10 minutes
Disconnect the battery.
(change the battery at this point if this is required, otherwise WAIT 30 seconds)
Reconnect the battery,
WAIT 1 minute
Keeping the doors closed, lean in via the drivers window
Switch on the 'ignition' (Don't start the engine)
Switch on lights (Dipped, normal driving lights)
WAIT 30 Seconds
Start the car "
or
" There is NO CODE on an original Picasso radio, the car and the radio are matched in the BSI using a computer.
However if the original unit is removed and replaced by another radio, be it a replacement citroen head or a aftermarket head then the BSI will not know the head. So you need the BSI to be told that it has to talk to a new head. This is done through a computer. "

To remember second information ? It is ok ? I don-t need radio-code ?
I will try this weekend to disconnect + cable if somebody tell me it is safe.

Regards
Mike

[Hell Razor5543]

As I understand it, when the radio is fitted to the car it is 'introduced' by use of the VIN (which is then stored in the radio). Even is power is lost the radio will retain this VIN. When the radio is turned on it communicates with the other electronics, and if the VIN matches the one the radio memory all will work properly. If it does NOT match the radio will start loudly beeping every few seconds.

This means that the radio does not require a code.

[GiveMeABreak]

The VIN code is entered in the BSI1 as well as in the Audio ECU (coded at the factory)
The 2 VIN codes are compared when the ignition is switched on:
If 2 VIN codes are identical, the Audio system functions normally.
If 2 VIN codes are different, the Audio system functions but permanently emits beeps
Disconnecting the battery will not remove the code as it is stored in flash memory.
The only time a Head unit will need recoding to the vehicle is if it is moved to another vehicle or replaced, or if the BSI is ever replaced.

[Mike60]

Thank you both for this helpful information.
" Even is power is lost the radio will retain this VIN "
" Disconnecting the battery will not remove the code as it is stored in flash memory "
Now I need to look forward what I bought
Best Regards
Mike

[GiveMeABreak]

Just follow the procedure you already found when disconnecting and reconnecting the battery - very important to avoid electrical problems and allow the car's computer network to properly sleep and wake up. So the not opening of any doors etc. when going through this and the timings are important.