Up-date - stargate 24.10.17 - I have finally had it confirmed by Jaguar technical that the EMS does shut down the electronics if you are say, fiddling with the screens to familiarise yourself with them (ignition on - engine off), or as I also was, pumping up the tyres with the digital inflator plugged into one of the auxiliary power units (ignition on - engine off) to protect the battery from too much drain. Ureka! Nothing in the manual though (apart from the reference to audio made in an earlier post by DJS) but all sorted now. Every day is a school day. :-)

 

I never use a tire inflator plugged into a cigarette lighter. Always only use alligator-type clips direct to battery. Invest in a decent pump w/ gauge and long air curly hose.

Cig lighter type is ok as onboard low-power emergency pump. Any pump with decent power will be too much draw for a plug-in and will pop a fuse.

 

Dave is 100% correct. Car shuts off the 12V receptacles after ~10 min. with ignition on and engine not running (knowledge empirically derived). Besides, unless the engine is running, the tire inflator is not receiving adequate voltage to operate most effectively.

 

Hit on off to get screen back on for 10 min. not sure if anything but radio, I use it while picking up grandson at school, have to get there early to get close in parking!

 

If you are talking about the sound system on/off button then yes, you don't need to have the ignition on (let alone start the engine) to turn the sound system on. Then when it shuts down after 10 minutes (you should get a one minute warning first) just hit the sound system button to turn it back on again and it continues playing from where you left off.

 

All sorted. Took the car into the dealer for a software up-date. Pronounced 'jerk' when engaging Drive, particularly when cold, completely gone. Lag at low speeds especially in comfort also gone. Much smoother and intuitive gear changes a transformation!