There are three different Freelander immobiliser systems:-
1. upto about 1999 there is no separate immo and it's all in the 27VT. These just have the remote central locking fob and that's all.
2. about 2000 to 2003 you have the fob for the remote central locking, and a chip in the key which links to the EWS3D immo. This is essentially the same system as the Rover 75 and is BMW based.
3. about 2003 to 2006 you have the fob for the remote central locking, and a chip in the key with links to the SAWDOC immo which I think is a JLR based ECU.
Concerning number 1, the upto 1999 you can mechanically cut a new key and program in a spare fob using a tool like pscan. These vehicles also have an emergency override EKA system like an MG Rover. If you don't know your EKA then it's worth finding it out and writing it down somewhere safe but not in the vehicle. On these early systems you can also rematch engine ECU to 27VT yourself with the right tools.
Concerning number 2 and 3 you can program in a fob as per 1 but it won't start the vehicle, because the chip in the key has to match what's in the separate immo. The chip in the key is activated and transmitted with via a coil in the ignition barrel. This works with no key/fob battery so in theory it's more reliable and more secure, but also more difficult to solve if you loose your key.
I know that if you have one working immo chip in the key that there are places that can clone them. So basically now I suppose that you would have two identically coded key chips. If you only have one then it's probably a wise thing to do now.
What if you loose the last one?
Three options that I know of:-
A. Landrover can supply (using the VIN) a brand new key with a chip that matches one of the codes that is already in your EWS3D or SAWDOC ECU. When these ECUs were produced the manufacturer put multiple codes in the ECUs and made careful records. So if you can get a JLR parts dept to supply one based on your VIN, then it should "just work".
B. There are tools that can "hack" the immo. Basically they can supply a key with a chip with a known code, and they they modify the immo ECU to put that code into the ECU so that the chip works. My understanding is that you can't do this through the diagnostic socket and the immo ECU has to be physically removed to access the right spot in the circuit board to hack it. This means getting the dashboard top off to get to the ECU. Less money to JLR but more money in labour to get to the immo ECU. If you can get the dash top off yourself then a good auto locksmith guy can do the rest quite easily.
C. Change the key chips, immo ECU and engine ECU for a working set from a scrap Freelander. Note that the engine ECU and immo are irreversibly linked so you have to change both. It's a complete three part "security chain" from the key chip to the immo to the engine ECU.
If anyone knows of more options then please let me know.
To be very clear about pscan and it's capabilities with EWS3D and SAWDOC: it can enable or disable key chips that are already linked to the immo, so when the codes already match. The usefulness of this probably limited to disabling a lost or stolen key, so if someone finds that lost key, or stole it, then you can make that lost/stolen key useless and therefore protect the vehicle. Basically if you loose a key and get a replacement from JRL then ideally you should do this. Secondly, if you then find that missing key you can re-enable it with pscan.
However, what it cannot do is create the link between a key chip and the immo that are not previously linked. So if you loose your last key chip then pscan won't help you.
The same rules apply to the JLR factory diagnostic tool.
I hope all that helps. Unfortunately it is quite complex.
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