Adding a extra Key fob

[headlight]

Hi all,

I was wondering if it is possible to add another key fob to my car.

I only have one doorlock on the car (Drivers door) and its broken. Ebay lists those transponder thingy's and the circuitboard for cheap so I rather add another key then try fix the broken lock.

I know onces a key is paired to a car, it wont work again on another car, but can you just program any "blanc" transponder to the car?

[Ozvtr]

I rather add another key then try fix the broken lock.

I have to warn you now, if you get a flat battery or the BSI/receiver fails, you will be locked out of your own car! The whole point of that lock is to get you into the car if ALL ELSE fails. A piece of friendly advice:- get the door lock fixed.

Theoretically the transmitters on Ebay should work and you can code them in yourself. If you want that key to start the car, you will need to do a bit more work.

[headlight]

I rather add another key then try fix the broken lock.

I have to warn you now, if you get a flat battery or the BSI/receiver fails, you will be locked out of your own car! The whole point of that lock is to get you into the car if ALL ELSE fails. A piece of friendly advice:- get the door lock fixed.

Theoretically the transmitters on Ebay should work and you can code them in yourself. If you want that key to start the car, you will need to do a bit more work.

Somewhere on the forums is a topic about pairing the fob, but I understand there must be done more in order to get the key working?

Problem with the lock is that it is near impossible to insert the key. If you try a million different angles and push hard enough it eventually works, but I agree its worth fixing

[Missing Lincs]

Problem with the lock is that it is near impossible to insert the key. If you try a million different angles and push hard enough it eventually works, but I agree its worth fixing

Hello headlight

If your lock barrel is stiff but still works then it's a definite candidate for penetrating fluid. An aerosol based product is ideal for getting fluid into the lock mechanism, give it a good 'squirt' let it soak for a while and then put some more on the key while gently working the lock. I think your problem is lack of use combined with ingress of water and dirt. As it's still partly working it would be a shame to break it by having to use force with the key.

As for adding extra keys, there are a few ways depending on what you want to do.

If all you want is a key to open the door (using the key in the lock) and start the car you can get your existing key copied, including the transponder. This is probably the cheapest and easiest solution as you won't need to programme anything on the car.

If you want the full works, including a fob to lock and unlock the central locking then you'll need a new key/fob from Citroen. This will then need to be programmed into the car either by a locksmith/garage or using a clone of Citroen's diagnostic tool 'Lexia'. These are useful tools to have for diagnostics but you need to decide if you need to get one and also support it with software and a laptop.

[headlight]

Problem with the lock is that it is near impossible to insert the key. If you try a million different angles and push hard enough it eventually works, but I agree its worth fixing

Hello headlight

If your lock barrel is stiff but still works then it's a definite candidate for penetrating fluid. An aerosol based product is ideal for getting fluid into the lock mechanism, give it a good 'squirt' let it soak for a while and then put some more on the key while gently working the lock. I think your problem is lack of use combined with ingress of water and dirt. As it's still partly working it would be a shame to break it by having to use force with the key.

As for adding extra keys, there are a few ways depending on what you want to do.

If all you want is a key to open the door (using the key in the lock) and start the car you can get your existing key copied, including the transponder. This is probably the cheapest and easiest solution as you won't need to programme anything on the car.

If you want the full works, including a fob to lock and unlock the central locking then you'll need a new key/fob from Citroen. This will then need to be programmed into the car either by a locksmith/garage or using a clone of Citroen's diagnostic tool 'Lexia'. These are useful tools to have for diagnostics but you need to decide if you need to get one and also support it with software and a laptop.

Thank your for your help. It is a lot more work then I anticipated, so I agree with both of you I better put some effort into getting that lock fixed. Soon as parts for my suspension arrive (diffrent topic) I will look into the lock as well. Its freezing here right now so I rather wait a bit untill I have acces to a heated garage

[Ozvtr]

The key/fob provides three levels of security.
1) The key blade. This provides physical protection against unwanted intrusions. Used with the door, fuel cap and ignition barrel.
2) The radio frequency transmitter for the central locking. This is more of a convenience than a security measure. It sends out one of potentially thousands of different codes and the car only recognizes that code from your fob.
3) The RFID chip. When you start the car the BSI sends out a pulse and the RFID chip in the key responds. The code that the BSI receives is sent on to the engine management unit. If the engine ECU recognizes that code, it begins operating the engine. If it doesn't recognize the code or there is no code the engine will crank over but it wont start. This is a passive component that does not require batteries and is completely separate to the radio frequency transmitter that opens the doors.

The first two, you and/or a locksmith can produce copies and code into the car. The third one requires a lEXIA or PROXIA and the 4 digit access code to the engine management unit (ECU). In amongst your documentation for the car, you should have a plastic card that looks like a credit card with Citroen written on it. This will have the 4 digit code printed on it or under a scratchable film. If you don't have this card or dont know the 4 digit code Citroen will provide it to you...after jumping through some hoops and paying some money. Without that code, keys (to allow the engine to run) can not be coded in!

Oh by the way, it's 38'C here in sunny Brisbane.

[routemaster1]

There may be a plastic card; however, Citroen seem to have stopped issuing them by 2007, so the procedure may well have changed.

[headlight]

Thanks for the detailed reply. I did not know about the RFID chip. 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.

-Edit-

The super helpfull comments made me think. 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.

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.

[Missing Lincs]

If 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.

If you want to programme a second remote control operator (the circuit board) you'll also need a new transponder (the tiny chip living inside your spare key). The way the car learns the new remote operator is for the unique code from the board being programmed into the transponder, then when the transponder is paired with the car using Lexia, the car also learns the remote locking part.

You can by new, genuine Valeo keys on popular internet auction sites, but, and it's an important BUT, the remote operator code is unlikely to be written into the transponder chip and to date I can't find how to do this. The only solution I found was to buy a new key with circuit board and transponder from Citroen.

You can buy just the plastic part of the key from a dealer minus the blade if you already have that part.

[Ozvtr]

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?

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?

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.