Citroen C2 locking issue

[GiveMeABreak]

Ok, what is crucial is that you report back on the fault codes here please.

We can't assume it is the fobs or transponder chips. There are other possibilities like the Comms unit inside the steering wheel that may not be communicating the info back and forth from the transponder coil to the BSI. If it cannot do this, starting authorisation won't be granted and it won't be able to programme the keys. It could also be why the issue is intermittent.

The other possibility is the transponder coil itself - it could be that the unit is faulty and another reason why the original owner had the transponder chip taped near to the coil as a bodge job.

The comms unit may also be at fault.

So as you see, there could be other possibilities. The fobs, once programmed don't become 'un-programmed', but can become unsynchronised, after a period of using from long distances where the number of rolling codes exceeds the 255 offset limit, necessitating the re-synchronisation process (which I think I posted earlier), which is of course not the same as re-programming the key.

So please report back on the codes as it may help with further fault finding - after you've had a bacon butty and a coffee of course!

[tomjyoutwit]

One error on the BSI and one on the injectors.

[GiveMeABreak]

If you press the return key whilst on this green message it should expand on the problem. But that will be the reason you can't code the key, whilst there is an immobiliser issue.

The second message is related. It is the Engine ECU that permits unlocking and starting of the engine. It won't do this if the correct codes are not sent through or if there is a communication problem.

[tomjyoutwit]

Hi Marc, I've uplaoded that screenshot now, meant to upload both at the same time but wifi out here isn't so clever!

[GiveMeABreak]

That error just relates to a fault in the electronic immobiliser. There's not a lot I can do with that error as it is a non-descript fault.

However as you have the Lexia - try going into the BSI / Engine ECU and looking at the status of the keys - does it say how many are programmed? Also, with the lexia still running, you can do some live data tests to see if the key data / recognition changes when you put the transponder chip near the ignition barrel.

So it still looks like either the key fob is faulty or the Transponder Coil, but without more info it will be hard to solve without playing 'parts darts' Tom.

[tomjyoutwit]

I’ll try that for you shortly Marc

[tomjyoutwit]

It looks like there are currently no keys attached to the car.

Two questions
- Would a key from a friend who has scrapped his car be usable?
- Is there a way to turn the immobiliser off whilst I get a new key shipped?

[GiveMeABreak]

No and No unfortunately, as that would defeat the purpose of it.

The transponder, BSI and Engine ECU are paired up and the BSI and the Engine ECU have to handshake using encrypted codes before the Engine Management ECU will unlock and allow the engine to start.

I think that whatever has happened previously has been a bodge and leading to the issues you are having now as the new owner.

[tomjyoutwit]

I have picked up a new anntenae from the scrappy- is there a way to test it before pulling everything apart?

[GiveMeABreak]

Here's an diagrammatic explanation of the system and the flow of information. So you can see there is a lot going on behind the scenes.

A Ignition key with integral transponder BSI Built-in systems interface CV00 Switch module at the steering wheel 0004 Instrument panel 1320 Engine ECU 6232 High frequency transmitter 8209 Transponder coil

Communication Flow

Link Number	Description of Signal	Nature of Signal
4	Transmission of part of the ignition key transponder’s identifier. If the ignition key’s identifier is recognised, the BSI performs the driver’s request (locking or unlocking of the doors)	High frequency link
5	(transmission of the ignition key transponder identifier). Transmission of the ignition key transponder’s authentication calculation	VAN CAR1
6	Transmission of the "BSI key"	CAN
7	Transmission of the random "seed" number (after the ignition key transponder authentication procedure). Unlocking information to the engine management ECU	CAN
8	Transponder fault warning lamp lighting request	Comfort VAN
9	Ignition key identification request. Ignition key authentication request (ignition key transponder password and random number)	VAN CAR1
10	Ignition key identification request. Ignition key authentication request	Analogue
11	Ignition key identification request. Ignition key authentication request	High frequency link
12	Transmission of the ignition key identifier. Transmission of the ignition key authentication calculation	High frequency link
13	Transmission of the ignition key identifier. Transmission of the ignition key authentication calculation	Analogue

[tomjyoutwit]

Is there a way to wipe keys at the locksmiths? I'm really not sure wheter to take the £60 hit or try and find a cheaper key on eBay as I have 3 blades that just need chips!

[GiveMeABreak]

Once they've been coded to the car that's it really.

As I said there are cheap fobs on the bay, but we've seen so many issues with them not working it really is a gamble. Some will be able to code them, but often the remote features won't work. They have to be the correct type.

Also you can't rule out other issues with the Comms unit or the transponder coil in the ignition. So if you want to try a cheap fob and try and code it you can - then if it doesn't work, time to investigate the other possibilities I mentioned.

[tomjyoutwit]

Thanks Marc,

Would you be able to compile a list of compatible keys, and their citroen part number and price so I can see my options?

Would one of the basic keys like I have spare for the C1 be compatible to save me a few quid and allow me to diagnose the issue?

[GiveMeABreak]

Hi Tom, I've posted my reply to your PM in relation to the Dealer here as it follows on from the thread:

I doubt it, as they will have the same info that I do - the technical information for this vehicle does not stipulate the frequency. It does on some later models - but I don't have anything and rather than guess I would rather be honest with you.

If you rang them up, you may find somebody that would consult the same info as I have and like I said it does not specify the frequency. So unless you got a particularly knowledgeable person who was a bit of an expert with direct experience of this exact fob for this model, year, architecture, it's not something they could necessarily look up, as it's not listed.

The other reason is that there are 2 types of fob that can be used, depending on the electrical architecture of the car. On your model there was 2 types of multiplexing - CAN CAN and CAN VAN. Each of these are different in both their bus speeds and data packet lengths and type.

Yours is fully CAN (CAN CAN).

The only thing I would suggest is get a cheap one to see if you can code it - if not send it back.
If Lexia fails to code a good blank and correct type of fob, then it tells me that there is another issue with the communication getting through as per the diagram I posted up. (10) & (13) are used to communicate with the rest of the system.

A dealer is going to charge you for a diagnostic - circa £90, so either borrow your mate's Lexia and run a FULL Global Test on the entire car, and report back any fault codes you may get first.

That will tell us if anything else is showing / suspect. But otherwise your transponder coil in the ignition may just be faulty as this is used to send the requests back and forth. I know this is frustrating, but stick with it Tom.

[tomjyoutwit]

Thanks Marc, have ordered a transponder only key that the manufacturer says will work just to test and hopefully have a running car!

I have a new aerial from a scrapped 207, no change using that.