Sounds like the RFID receiver antenna (for the 'smart' key) on the steering column. There's one reference to it in the wiring diagram, but no specifics.

 

Correct mechanic terminology is key exciter coil
Part number lja2668ab also listed coil-key transponder
they also had to reprogram all keys

 

Interesting that ALL of the Jag wiring diagrams across the years 98-02 for XJ and XK have one and only one reference to 'reader/exciter' in the body of text with a referral to schematic figure 13.3, for instance, but in every year/model wiring diagram, that referenced figure is not included. (for example, look at page 8 of the 2000 XJ wiring diagram - exciter refers to figures 13.3 and 13.4 - NEITHER of which are in the document)

The key transponder module is shown in all docs, but without any cross reference to the exciter coil... are they one and the same? The part number that BigCat provided does refer to 'Coil/key transponder' so it must be at least part of the key reading RFID system - it's just not shown in the schematic diagrams, which is frustrating. Also, the cost is around $20, which, to me, implies that it's not the module itself, but that it's just the coil that connects to the module.

I find this rather unusual - the first time I've found any of the Jag wiring diagram information to be lacking or confusing.

 

I found this unusual also and so did the technicians at the Jag dealership. The codes all pointed to the bpm and when that didn't work they were left scratching their heads. If one of them didn't offer to swap parts, my car would have just been a rather large paperweight.

 

Do you have copy of repair from the dealer that can fax for me to show the TECH? Matter of fact can you post a copy for me print on the Forum

 

Inspected and found engine would not spin- jumped starter relay and engine spins over-checked for signal to relay- no signal present- performed immobilization relean and key programming condition still present- checked resistance of wiring from bcm to starter relay-ok- monitored security status and found bcm not changing- ecm and bcm get the same signal on the same wire from the key transponder module- ecm was changing- suspected faulty bcm- replaced bcm with part from client- condition still present- swapped key exciter coil from known good vehicle and engine started- replaced key exciter coil= programmed key to vehicle- vehicle starts and runs

This is all i have from dealership.

 

Well, there it is- another exciter ring being the root cause of no start.

 

Thanks again for the follow through bigcat, it could be really helpful to others
I'm gonna mark this thread *fixed - FAQ* and one of the mods will add it to the FAQ section

 

Well today they (dealer) had a hard time starting the car so they replaced the battery (as usual) BUT to see if that might be the problem. They are keeping the car overnight again to see if it starts. Then I guess they're move through there set of test on the electrical system. I am going to use this info that you gave me and show this to my Service Advisor so tomorrow they'll have a real starting point on diagnosing this. Thanks so much for info.

 

Kudos to you! On the road again!