Adding a extra Key fob

Missing Lincs wrote: ↑Sat Nov 16, 2019 4:14 pm

headlight wrote: ↑Sat Nov 16, 2019 9:50 amIf my assumptions are correct I only need the circuitboard now in order to get a fully working key.

Your assumption is correct, however if only it was that simple. The circuit board needs to be programmed to the car, this can only be done with Lexia or an electronic key programmer with the capability.

The central locking transmitter (the circuit board and battery) can be programed in by the user. At least on the original shape (MK1) that Headlight has.
Insert the key into the ignition lock. Turn the ignition to ON and press the lock or unlock button. Turn the ignition off and withdraw the key. Done.
However the RFID chip does need a LEXIA, PROXIA or one of the new generation of key programmers to code it into the engine ECU.

Ozvtr wrote: ↑Sat Nov 16, 2019 4:39 pm

headlight wrote: ↑Sat Nov 16, 2019 9:50 am Amongst the documents of the car is indeed a plastic card, but its as usefull as a chocolate teapot. The card has no information on it, nor could I scratch it.

Look on the back, is there anything printed in the top corner?

headlight wrote: ↑Sat Nov 16, 2019 9:50 am The spare key has this little thingy inside made by Philips. It is the only part inside they key so I assume that little thingy is what needs programming.

No (Yes? I'm not sure what you mean), that's the RFID chip. Your engine ECU will already have that code in it. If you move that to your new key the engine will start.
That looks like a "valet key" as there is no room for a transmitter circuit board in it. It can only start the car it cant (remote) lock it? I have never seen one before. In some other cars that chip will only allow the engine to run for a certain period of time but I don't believe the C3 has that mode. Will the engine run without stopping on that key?

headlight wrote: ↑Sat Nov 16, 2019 9:50 am A few days ago I ordered the bits needed for upgrading me key to the folding style one. So I have a empty shell, with allready cut blade. If my assumptions are correct I only need the circuitboard now in order to get a fully working key.

Yes but you still have the problem of your car not responding to the transmitter. However if you got a new transmitter board before your car went to Citroen you could still try it again.

Here in the Netherlands cars come with two keys. Usually there is a "main key" wich is more luxurious and features the remote for operating the central locking and there is a Spare key wich lacks the remote function but works as a normal key in every other way.

So by comparing the inside of both keys I know that little RFID chip is all you need for starting and running the car. But that is where it gets interesting.

I think (after reading the comments in this topic and some other topics) the RFID tag and remote are two different systems. Now for the RFID tag it makes sens to have a very secure procedure for adding keys. But for the locking/unlocking I would say its less of a issue. (For breaking into the car there are much easier ways to get in then to copy a key, and its useless sinds you cant start the engine)

But that kinda leaves the question how to add another remote. I think @Ozvtr is right and the reprogramming procedure is all it takes.

Im really curious to see if it works, so I just orderd a circuitboard on Ebay. If im unable to pair the circuitboard myself I will take it to the Citroen dealer. One way or another we will get a definitive answer wich might be usefull for anyone else trying to do the same or replace a broken remote

headlight wrote: ↑Sat Nov 16, 2019 9:43 pm
So by comparing the inside of both keys I know that little RFID chip is all you need for starting and running the car.
I think (after reading the comments in this topic and some other topics) the RFID tag and remote are two different systems. Now for the RFID tag it makes sens to have a very secure procedure for adding keys. But for the locking/unlocking I would say its less of a issue.

Yeah, you got it.

After all this cr@p with security and coding and stuff, the easiest way to steal a car...is to steal the key!!

So the housing finally got in, but i stuffed up ordering a replacement instead of a upgrade housing so ofcourse the circuitboard doesnt fit. To make things worse I only discovered this after having the blade cut (wich wasnt cheap).

But as it turns out its not so bad. While both original keys are unable to operate the fysical lock, the newly cut blade works perfectly fine. Will keep an eye on it as it seems odd to have two bad blades but for now at least I didnt waste my money on a useless key.

I just ordered the correct housing, so that gets rid of that problem.

The replacement circuitboard I ordered hasnt arrived yet, but for good measure I will see if I can add it to the car.

The parts only came in yesterday.

I was able to add the extra circuit board by using the pairing methode, so that question is answered.