Hello all. Just bought a 95 sovereign and though it drjves like is bit rough round the edges.
This may seem strange question.
, but is it possible to disable the security system?
I have only 1 key, and a fob that doesnt work.
I feel for our family use, a new key and no fobs is going to be easier for us.
Can i simply unplug it?

 

Welcome to the forum, Scotsman. Please drop by the new members section and make an introductory post so you can enjoy the full benefits of this fabulous forum.


Meanwhile, you may find that your FOB need only be programmed to the car. Give it a fresh battery and refer to the owner's manual for the procedure (Available here in the "Stickies" if you don't have the paper copy)


On the other hand, I'm not sure I understand your question. If you obtain a proper second key, the security system should pose no problem. Inserting a valid key in the driver's door to unlock it will prevent the sound and light show, and should start the car.


Others may happen along with a better grasp of your question and how to answer it. I'm thinking while perhaps possible, it would be more trouble/expense than it is worth.

 

Hi, thanks for the reply.
Problem i have is my current doesnt work. Changed battery with no luck.
I just thought it would be easier to just disconnect the system and open and close with a key?
Do the keys have transponder chips in them?

 

UK spec cars have a transponder chip. The car will crank but not start or run if the key is not recognised. The key fob only controls the alarm. Using the key in the door lock does the same thing as the key fob.

 

Thanks. Can you think of a reason the alarm wouldnt read the transponder? It seems to be a bit intermittent.

 

The components involved are
1. The transponder chip in the key itself (unlikey as these are generally very reilable).
2. The exciter coil fitted around the ignition switch barrel - this energises and reads the key (unlikely unless you have been working at the wiring around the steering column).
3. The exciter module fitted behind the trim panel on the left below the steering coulmn - this is connected to the coil above and reads the key.
4. The security and locking control module (SLCM) in the boot behind the fuel filler neck. This receives the signal from the exciter module and checks against the registered keys. If the key is recognised it sends an encoded signal to the ECU to disable immobilisation. This module can only be programmed using dealer level diagnostics to pair with keys.
5. The ECU disables fuel injection and ignition until the correct encoded communication is received from the SLCM. Because it is integrated within the ECU the system cannot be simply overriden or unplugged.


Once the key has been successfully read and the engine has started these security components play no further part until the ignition is switched off so it is unlikely that they are responsible for intermittent behaviour during running.

 

Thanks for that. Very helpful.

So like you say, the immobiliser is unlikely due to the intermittent cutting out when running...

bugger. That would have been too easy I suppose!

Fist problem I have is getting the damned thing running, it wont even try now. Have no idea if there is a spark or fuel as I've not had time to look at it yet.
I'm still convinced it's an electrical problem though. Will have to start going through every fuse and connection I can find and see what happens I suppose.

Cheers

 

See this post for a collection of no start problems.
https://www.jaguarforums.com/forum/x...ngines-120221/
A common issue -
Crankshaft Position Sensor - on cranking the rev counter should show a reading if this is working. It does not produce a fault code and there is no easy way to test. It can be intermittent (mine was, occasionally failing to start - that's why I know about immobilisation!).
Some owners have also reported corrosion on the ECU pins due to water ingress. It is behind the trim panel on the right in the drivers footwell.
Other than that it's working through the problem systematically and don't forget to check for fault codes.