Well, I did it... I went to add/remove new "stuff" to the 04 XJR with the JLR SDD software and in that part it said it was going to deprogram my keys and then it would reprogram them. So I said OK. Then it said I needed TWO keys and I have only one(1) that is cut that came with the car and another with a blank that just came in from eBay. I programmed the FOB on the eBay key so it'd function in that capacity until I can find someone to cut the blank. Well, not the car won't start. Both FOBs still work, but when I insert the original key into the ignition, the seat and steering wheel come to the correct position and when I turn the key to position I and II, it seems fine, but it will not start the car. I FINALLY found a place that will cut my blank, but not until tomorrow.

When I do get it cut, I should be able to go through the programming again and have TWO key as it says I must have TWO keys. I tried to use the same one, I tried swapping over the electrics part over, and a few other things to try to fool it, but it won't work. Thoughts, opinions, etc???

HELP!!! (I'm SEVERELY irritated with myself right now as well)

Reading the HOW TOs now... will update with info...

had the same problem once,turned the key and all dash lights came on, but when turned to start nothing! I remember reading once to remove the ground cable from battery and touch it down on the hot post to reset everything.Started right up, I think that same day before I got to the car that the alarm went off a few times. Not sure if that was related.
Good luck
Bill
1998 XJ8 VDP

Hi ragman1171,

Here is a screen print of the SDD screen on programming keys from SDD version 128. I am not sure which menu option below you chose to use but each one is different in programming your keys.

First you do need to have all keys ready, so you do need to have the key cut and thus keyfob ready for SDD programming. What happened is that SDD errassed the transponder code with your car (transponder chip is in the upper blade portion of the key fob) and thus your car will not start.

In programming key fobs there are three menu choices:

"Security - Program additional transponders" - which will program additional keys (upper portion that has the transponder chip)

"Security - Program new keyfob transmitters" - which will put you through the steps of reprogramming the entire key fob (upper portion that has the transponder chip as well as lower portion that has the buttons) which means first all existing keys will be errassed from working with the car and then reprogrammed by following the SDD steps.

"Security - Program new transponders" - which will program the upper portion that has the transponder chip)

You could try "Security - Program new transponders" to get your one key programmed again. But I would first get the key cut and then with all keys in hand run the "Security - Program new keyfob transmitters" menu option.

I wonder what the difference is between "Security - Program additional transponders" and "Security - Program new transponders" if they both program the upper portion of the fob with the transponder? Wouldnt additional transponders always be new?

The first is for programming additional transponders and the other menu is for erasing all existing transponders and reprogramming a new set of up to 8.

Thanks for the clarification. So "Security - Program additional transponders" should keep your existing transponder 'signature' in ECM and any additional ones get added. This is very helpful to know so as to avoid the issue Ragman had in loosing the ability of his one key to start the car.