Car keys of Citroen C5 Tourer 2011

[GalianoGalianei]

Hello everybody.
Recently I encountered an issue with my car keys where it just stopped working for some reason. I thoight that the problem was the battery so I replaced it with the new one and then the car key worked fine, but only for 2 days max, and that is the same for every new battery, so up to 2 days max. Does anyone know what is the issue, what might be causing it and is there any way to fix it. The battery is CR1620 I think, I hope that helps.
Thanks to everybody in advance.

[Paul-R]

What has stopped working? The ability to remotely lock the car or the ability to start the car?

[GalianoGalianei]

What has stopped working? The ability to remotely lock the car or the ability to start the car?

The unlocking and locking of the car remotely stopped.

[PaulC5]

Are the batteries you are using from the same supply - if so they might not be any good.

[wheeler]

The car should start regardless if there is even a battery in the key.
As above i would try a different brand of battery from a different store to rule out faulty batterys
Failing that check for obvious damage on the circuit board, could also be a fault button sticking causing it to transmit all the time, may well need a new remote

[Paul-R]

If there is a decent locksmith nearby they may have a machine which read whether your remote sends any signal out when the buttons are pressed.

Have you tried resynching the remote?
Put the key in the ignition, press either of the lock/unlock buttons and then turn the ignition on. Keep the button pressed for about 10 seconds and that should do it.

[GalianoGalianei]

If there is a decent locksmith nearby they may have a machine which read whether your remote sends any signal out when the buttons are pressed.

Have you tried resynching the remote?
Put the key in the ignition, press either of the lock/unlock buttons and then turn the ignition on. Keep the button pressed for about 10 seconds and that should do it.

I tried resyncing it, that is not the problem. Maybe I need to check for different batteries and see if it works. Thanks for reply.

[GalianoGalianei]

The car should start regardless if there is even a battery in the key.
As above i would try a different brand of battery from a different store to rule out faulty batterys
Failing that check for obvious damage on the circuit board, could also be a fault button sticking causing it to transmit all the time, may well need a new remote

Thanks for the reply. I will try the new batteries and see if it works.

[GalianoGalianei]

Are the batteries you are using from the same supply - if so they might not be any good.

Same supply. I will try to find new ones. Thanks for the reply.

[wurlycorner]

Can't offer any help on this unfortunately, but just to say that the second key for my 2011 C5 X7 Tourer suffers the same problem, so I'm interested hearing what you find as the solution.

[Paul-R]

If it's of any use to people, the replacement key I ordered for my 2013 C5 X7 through Aliexpress in 2019 was ASK.

It of this type, although not from this supplier:
https://www.aliexpress.com/item/1005008 ... ry_from%3A
Note that they reckon the changeover from ASK to FSK was in 2011 which is not what I found.

[wurlycorner]

What's the difference between ASK and FSK? Not sure I can see?

[wheeler]

Its the type of frequency, a bit like AM & FM

[wheeler]

My 2010 X7 was also ASK