Hey guys,

is the immobilizer of the XJ in the engine ECU or the Instrument cluster? On the old X300 it was a little unit on the back of the IC. Is it the same on the X308? The antenna is around the lock. But that is only where it is read. Where is the signal processed?

Cheers

Damien

 

Judging by the electrical guide (free download) it's done by several modules all co-operating.

 

The immobilizer is based on the dedicated key transponder module, which works together with body module and engine control module

 

The starting sequence for the x308 is as follows.
1. The key inserted sends a signal from the key transponder to the the exciter ring in the ignition switch.
2. The exciter ring send the signal to the SCLM (security control locking module. The module is mounted on the underside of the boot fuse box.
3. The SCLM sends a signal to the ECU that the key is recognized and the ECU allows the engine to crank.
4. Initial turning of the key starts the self check program and turns on the fuel pump for 3 to 5 seconds to charge the rack.
5. Continuing turning the key engages the starter and the crankshaft position sensor notifies the ECU of engine rotation.
6. Once notified of rotation the ECU activates the run program providing injector function and coil firing.


If you are experiencing a no start condition it would be helpful to no what year and engine you have. And if it is a no start/no crank condition or no start/cranking condition.

 

Okay, so, the key code read by the code reader ring, is processed in the security module. So that is the part which is paired to key, lock and RFID tag in the key.

Reason I ask is because my car is being stripped. People have asked about the ECU but I wasn't sure if some kind of lock might have been in place...

​​​​

 

That is correct DAIM. Transponders are programmed to the SCLM. It takes dealer level software program the transponders.

 

Thanks for that. I wasn't intending on selling bits like that but of course if it works with my keys, I can pass on the locks with the SCLM and in theory, it should still work... Should...

 

There are certain modules that make up the CAN system. My understanding is that when you change a module that is part of the CAN then it has to be programmed for the CAN to accept it or you get a dash indication of "incorrect part installed". I think the ECU, BPU, TCM, SCLM and the Climate control are all part of the CAN.
At any rate, these modules all have to be programmed when installed. They are not just plug in and play like a seat controller or door module. Anyone contemplating buying a used module should know they have to have it programmed,

 

....and, all the modules are listed along with the part numbers & program codes on the VCATS sticker located in the trunk around the spare wheel well.
When armed with the specific numbers you can skip the part for dealer level reprogramming as long as the part replaced matches exactly.

 

That holds true for all modules except the SCLM. The SCLM stores the RFID number from the the key transponder. Plugging it into a new vehicle with matching VCATS will not allow the car to start since it doesn't recognize the RFID from the transponder. If you remove the entire ignition and SCLM you can install them in a matching VCATS and the vehicle will start.
Just swapping the module requires the transponder to be programmed to the SCLM.

 

Ok, so, this means:

The ECU as well as other 'xCU's apart from the security one would need reprogramming UNLESS the numbers on the 'xCU' is the same as intended to replace.

So, let's say, the ECU is 11.111.1A and the receiver car has 11.111.1B, then it isn't granted to work. BUT it might be able to... If replaced with the exact same code, then there is no issue, right?

​​​​​​Cheers guys!

 

Hello, my cat is a Daimler 6 1995 x300: is it the same? I have no key and I'm stuck. A locksmith failed in programming transponder (EEPROM in the reader exciter?) any idea? If I want to buy a set (barrels, key) do I have to find reader exciter+security module, all from the same car? Thanks

 

brett, you would probably get a better response for your problem if you post your question in the X300 forum. https://www.jaguarforums.com/forum/xj-xj6-xjr6-x300-26/

I am not familiar with your vehicle but I know that in the 1997 XK8 there was no RFI chips used. I doubt there was any in 1995. I am pretty sure the technology came later. It might be you have a different problem

 

thanks for yous answer. actually there is a difference between American market and european market. In 1995 they hadn't chip in US but they had in europe. But it changed after the Vin 758729 then US cars had chips.

 

The FIRST Jaguars to have the RFID and Key Transponders for the North American market was 1998MY (both X100 and X308).