I'll be taking the 05 XJR North for Christmas. It is a Florida car with the original battery. It so happens I have a spare battery that I can carry along in case of cold weather failure. The current battery is good but it has some age and has never seen a cold day.

It used to be that one could change a battery without losing stored code info buy pugging a small 12V source into the cigar lighter before removing the battery. Is that a workable solution with modern Jags?

The reason I ask is there seems to be a lot of stuff dependant on the battery in this machine and I'm not sure this old trick is still valid.

 

I asked my dealer this question and the answer I got from them was they use a battery tender plugged into the cigarette lighter when doing a battery change....

- Tim

 

A cheap easy way to do this is a cigarette lighter plug attached to a 9v battery plugged into the lighter. The 9v is enough to hold the memories.

 

The Battery in the cigarette lighter technique is known to me. In fact I have used it successfully a few times in the past.

What concerns me is that these cars have so much memory stored here and there that a 9V battery may not might not be up to the task.

Has anybody here actually successfully used a 9V battery on a 2000 or later Jag to save memory during a main battery exchange?

 

I bought a 9v memory saver device for mine a while back but havent used it yet.
If the worst came to the worst cant you just press A.Mem, PTY and >> to get the radio code (as long as its the radio from the factory) and press and hold eacj window switch for 2 seconds in the fully up and then fully down positions to re-enable the one touch window open/closing?

 

Didn't know about the radio code thing! I'll have to try that. The 9v battery should work fine as the memory uses very little power(or else you would have a constantly dead battery).

 

Thing that concerns me the most about trying to preserve memory with a 9V battery during a main battery removal and replacement is not just the radio. I was thinking about the seat, pedal and stearing wheel memory. Not to mention the cars system set up and nav. settings.

I,m not really sure how all this memory is retained, but it seems like a tall order for a lowly 9V source. That's why I was interested in hearing from someone who has actually tried the 9V batt. It seems to me that we do have an answer, in that one poster said his dealer uses a "batt. minder" to provide the power during batt. changes. My guess is that a quality service dept. takes no unnessary risks.

 

I hate to ask an ignorant question, but here goes. I've read in several other posts that people have trouble-shot other electrical problems by disconnecting and reconnecting the battery. If replacing the battery wipes the memory, why doesn't a disconnect/reconnect do the same thing?