OK, this was weird.
 

Yesterday, while driving, I changed stations on the radio and the screen went to the Jaguar graphic. I stopped the car and turned the car off but the radio kept playing and I couldn't turn it off. I started the car and drove a couple miles further and turned the car off again. Radio kept playing. I left for ten minutes came back and started the car and the screen was back to normal. What the heck happened?

Take pics with cell phone as dealer can never reproduce that stuff/

Obvious first question is how old is your battery?

Interesting question about the battery. Had a new one installed last year. But i'll get it checked. Thanks.

If it is a regular lead acid battery, even only a year old, it may not be able to keep the voltage levels steady considering all the electronics in these cars.

Absorbed Glass Matt (AGM) batteries are the way to go. Interstate sells these...they are more expensive but better in the long run.

Thanks, I'll look into it. Dumb question...how do they test to tell if your battery needs to be replaced?

They will hook a machine to it that will put a varying load on the battery and see how much the voltage and current fluctuates under that varying load. You can get this done inexpensively at many auto parts stores.

If during the test the voltage ever drops below 12.5 volts, that battery will most likely start giving problems with "gremlins" in your electronics (for these Jags). That same battery may be fine in a Ford, GM, or Chevy...

Some may have other information...

The only thing that has me not thinking about the battery is that the op indicated the car was running.

The alternator should easily put out a regulated 13-14 volts while the engine is running.

Not a lot on modern cars tha can suck down a 90 amp system, but i supose if you were running a lot of stuff you could get close?

Vince

So the big question then is, if not the battery, what else could it be?

Well it was the turning the car off part that I was keying on. I'm assuming everything worked fine while he was driving. If the screen went to the Jaguar logo screen, I'm assuming he could have went back to the radio screen if he had wanted to.

So, "he", is that the case? :)

Also, I know my wife's 05 VDP computer "shuts down" after 6 minutes when the car is turned off.

Locking the XK causes the computer to shut down many functions that are active when the car is in use; not sure how long it takes to "completely" put all the functional systems to sleep that do sleep.. The extended time the car was off most likely caused this normal shutdown which most probably eliminated the "glitch" that was experienced.

Actually, no. The screen went to the Jaguar logo screen while I was driving. But I was unable to get back to the radio or any other screen. It was locked on logo, with the radio playing. It finally straightened out after I got out of the car. locked it and left it for about 10 minutes. It was back to normal when I returned.

Can u elaborate a bit...what buttons did you push to try and change the screen? Did you try the manual buttons under the screen? etc...

Yes,
I tried the buttons under the screen and got no response.

One other possibility: Over the last few days I've been using Google Maps on my iphone and have the phone connected to the lighter receptacle to keep it charged. I wonder if that can be causing problems?

I would say no...

Well, the only thing I can speculate on what may have happened is that there was a unique combination of screen choices made in a particular order or series that may have hit some boundary condition in the execution of the software which caused the screen to "hang". Resetting the system obviously took care of the situation.

If it happens again, or begins to happen with more frequency, you may need a software update, or the computer which drives/manages the headunit may be developing a fault. You might want to get the dealer to read your computer and ensure you have the most up-to-date software.

Not much else to go on at this point.

OK thanks. I will get the battery checked however. That's still a possibility.

Diagnosis: It was the battery. Replaced it this afternoon.

Thanks for coming back to us with the fix!

V