Remote key, FSK or ASK?

[LarsS]

Hi
How do I know if the remote key is FSK or ASK?
/Lars

[GiveMeABreak]

If it's for your Citroen C3 in your profile, it's probably ASK - but pop your VIN up and I may be able to help.

[LarsS]

If it's for your Citroen C3 in your profile, it's probably ASK - but pop your VIN up and I may be able to help.

Yes it´s for my C3, VIN-code: VF7**************[VIN obfuscated, can be read by forum staff]
/Lars

[LarsS]

If it's for your Citroen C3 in your profile, it's probably ASK - but pop your VIN up and I may be able to help.

Hi again. I joined the the forum today. Now I've donated a little gift to the forum.

Yes it´s for my C3, VIN-code: VF7**************[VIN obfuscated, can be read by forum staff]**************[VIN obfuscated, can be read by forum staff]
/Lars

[GiveMeABreak]

Hi Lars

Thanks for the Forum donation, please ask if you need any official part numbers, which should cover you for requests for the next 2 years.

The part number for your fob is 6554 NR. This should be a 433 MHz ASK.

[bebu190]

Hello & Good morning,

I'm Benjamin, I'm french and just registered a minute ago on this forum.
I have kind of the same issue here i think my car key is dead. The car will open and lock remtotely but won't start the engine / the vehicle, so I changed the key battery but still, the car do not want to start.

I guess it's not the transponder (the coil which act as an antenna if i understood correctly) but probably the RFID chip who's either dead or uncoded i don't really know to be honest.

Anyway i was thinking about ordering a new car key (it's a 0523) however i do not know if this work in ASK or FSK. I've seen 0523 car key in ASK and FSK...

Could you tell me and advise me also on which frequency it is for my car ? ASK or FSK ? it's a citroën C3 II from October 2010

Thank you all,
Benjamin

[GiveMeABreak]

It's possible your Fob has become unsynchronised - which it can do if you replace the fob battery.

Before ordering a new one, try this first of all:

For standard vehicles, with the key still in the ignition and within 10 seconds of switching the ignition on, hold lock button on key fob down for a few seconds (to synchronise the remote fob).
Switch off ignition and remove key
Repeat this part for any other fobs if required (especially if the battery was previously completely flat).

Are you getting any messages on the dashboard?

[ozvtr]

The car will open and lock remtotely but won't start the engine / the vehicle, so I changed the key battery but still, the car do not want to start.

There are two independent parts to the key electronics. The transponder and the transmitter.
The transponder is a small 'unpowered' chip that communicates with the engine ECU to allow the engine to run.
The transmitter has a circuit board and a battery and transmits a signal over a small distance to lock and unlock the doors.
If you can lock and unlock the car remotely, using the key, there is nothing wrong with the Transmitter.
You can only re-synchronize the transmitter not the transponder.
However, if the car wont start, might be to do with the transponder. The transponders are very reliable and apart from perhaps crushing them, they are pretty well indestructible! I have never heard of one just stopping from working! The transponder arrangement has been used by many manufacturers for a long time and is very reliable.
The HF module is the next line in the security process and receives the information from BOTH the transmitter and the transponder. So if the doors lock and unlock then then you can assume the HF module is working. The HF module receives the information from the transponder via a coil around the ignition barrel. It's possible there is a problem with the coil, the connector...or such.
I don't suppose you have a second key? Hmm that would be too easy! If the second key did the same thing, the problem would be in the car.
There is actually a complicated procedure to communicate from the transponder chip to the engine ECU but it would be unheard of for just the immobilizer path to fail. Some of the scenarios are possible, but highly unlikely.
The other option is a failure of the engine or engine ECU.
The problem might not be the key at all.

[wheeler]

Before buying a new key I would try reprogramming the one you have with diagbox, you will need the 4 digit security code for this.

[bebu190]

The car will open and lock remtotely but won't start the engine / the vehicle, so I changed the key battery but still, the car do not want to start.

There are two independent parts to the key electronics. The transponder and the transmitter.
The transponder is a small 'unpowered' chip that communicates with the engine ECU to allow the engine to run.
The transmitter has a circuit board and a battery and transmits a signal over a small distance to lock and unlock the doors.
If you can lock and unlock the car remotely, using the key, there is nothing wrong with the Transmitter.
You can only re-synchronize the transmitter not the transponder.
However, if the car wont start, might be to do with the transponder. The transponders are very reliable and apart from perhaps crushing them, they are pretty well indestructible! I have never heard of one just stopping from working! The transponder arrangement has been used by many manufacturers for a long time and is very reliable.
The HF module is the next line in the security process and receives the information from BOTH the transmitter and the transponder. So if the doors lock and unlock then then you can assume the HF module is working. The HF module receives the information from the transponder via a coil around the ignition barrel. It's possible there is a problem with the coil, the connector...or such.
I don't suppose you have a second key? Hmm that would be too easy! If the second key did the same thing, the problem would be in the car.
There is actually a complicated procedure to communicate from the transponder chip to the engine ECU but it would be unheard of for just the immobilizer path to fail. Some of the scenarios are possible, but highly unlikely.
The other option is a failure of the engine or engine ECU.
The problem might not be the key at all.

First of all thank you all for your answers !! i do have a 2nd key and the engine do start indeed so I can use my car normally however this second key has no remote lock/unlock features. I need to lock the door manually everytime i leave the car.

So for me this has nothing to do with the car but more the key.... I'm not sure I understood all your explanation but I also thought about the coil.... because it is quite exposed on a 0523 circuit board... but the coil seems ok with my naked eye ... no trace of damage or such...

But if I summarize correctly there are 4 main electronic parts: the transmitter, the transponder, the HF module, and the coil it's weird i don't see that many "active" electronic parts on the board. Anyway i have in my possession another coil cause this is the first thing i thought of so i ordered exactly the same model "245 coilcraft" model

[bebu190]

It's possible your Fob has become unsynchronised - which it can do if you replace the fob battery.

Before ordering a new one, try this first of all:

For standard vehicles, with the key still in the ignition and within 10 seconds of switching the ignition on, hold lock button on key fob down for a few seconds (to synchronise the remote fob).
Switch off ignition and remove key
Repeat this part for any other fobs if required (especially if the battery was previously completely flat).

Are you getting any messages on the dashboard?

Hello Marc,

I tried that indeed holding the lock button for 10 seconds and all it didn't work.
Some forum, some other post i found say you need to use your functional key start only the electronic part and quickly within 5 seconds turn off and insert/start with the non functional key to "reprogrammed" the car key.

However I did not try that i'm afraid this might deprogrammed the one that still works

[bebu190]

Before buying a new key I would try reprogramming the one you have with diagbox, you will need the 4 digit security code for this.

Hi wheeler,

Thanks for sharing and helping.
Yes but i do not possess a diagbox this is something also i should see with a garage owner if they have such tool ... not sure if all garage do have one

But again as ozvtr suggested transmitters only can be reprogrammed not transponders.... and transmitters seems to work as it unlocks doors.... that's pretty odd, I've seen that they are greater chance that the issue come from the coil i don't know really

[wheeler]

Before buying a new key I would try reprogramming the one you have with diagbox, you will need the 4 digit security code for this.

But again as ozvtr suggested transmitters only can be reprogrammed not transponders....

The transponder can be reprogrammed back to the car it was originally programmed to just not to a different car. Well actually remote keys with the ‘chip on board’ type transponder can be flashed & re used on a different car but you can’t do it with diagbox, you need another tool for this.
Remember all the vehicles keys need to be reprogrammed at the same time or they will be forgotten by the BSI.

[ozvtr]

That's not the coil that I was talking about. That's the antenna (coil) for a PCB transponder. I don't want to make this thread more complicated but you can get keys that have the transponder as part of the circuit board or the transponder is separate.
To my knowledge the genuine keys have a circuit board for the transmitter and a separate ID46 transponder 'chip'. I have only seen the Chinese knock-off keys use the "on PCB" type transponders with the discrete coil. So I don't think your key is original, but....I could be wrong.
Seeing as the second key works (which would have made this thread much shorter if you had mentioned that in the first place ) you can get a new transponder "cloned" and replace the transponder that doesn't work.
A locksmith or auto locksmith can clone a transponder but they need an original transponder (or whole key) that works with your car.
Or you could just take the transponder out of the working key and put it in the non working key. Of course, that wont work if the transponder is soldered onto the circuit board.
I am not sure but I think there is something strange going on here.
I would recommend taking both keys to a locksmith and see if they can sort it out for you.

[wheeler]

That's not the coil that I was talking about. That's the antenna (coil) for a PCB transponder. I don't want to make this thread more complicated but you can get keys that have the transponder as part of the circuit board or the transponder is separate.
To my knowledge the genuine keys have a circuit board for the transmitter and a separate ID46 transponder 'chip'. I have only seen the Chinese knock-off keys use the "on PCB" type transponders with the discrete coil. So I don't think your key is original, but....I could be wrong.

The majority of PSA cars now have 'on PCB' type transponders & not seperate transponders on the remote keys. This is how they can be flashed & re used on another car with the right tools.
Yes the ID46 transponders can be cloned but this is no good if you want a remote key as like you say its the transponder that gets cloned.