X260 MY16 25t petrol here
​​​​​​I have been experiencing odd situation this pass few weeks. It happened 3 times now, at the same parking lot, around the same parking area, right after ice hockey practice, that I'm unable to unlock my car - (I do not have touch unlock), then after 3-5 mins, it mysteriously works as normal.
Last week, after drop off kid to school, stopped at the grocery shop then suddenly I couldn't start the engine and not even ignition on. I was able to lock and unlock the car, open the trunk, hunk the horn. But since I can not get the ignition on, the electronic handbrake can not be released. Took it to the dealer by a tow truck to check and no error code with OBD reader. They remove the dashboard to check if there's any faulty wire or button from the start engine button all the way to the ECU, and nothing to show for. Checked the key and car battery are both healthy. Unplug the car battery to power off the ECU, then the next day it is back to normal. Car dealer returned the car to me and asked me to test it out, since nothing is at fault. They will suspect a faulty ECU but again no evidence or error code to conclude at this point.
About a week of ordinary driving later, everything seems normal, today I went to the hockey rink and after practice i couldn't unlock my door again... and after 3-5 minutes, I was able to unlock it and everything is back to normal again.
Any thoughts guys, can really use some help here, feel like dejavu again.

 

First 2 things
1) Is the 12v battery is still OEM in your 2016?
2) Also, when was the last time you changed the key fob coin battery?

 

1. Changed car battery in 2021 at the dealership, so yes
2. Key fob battery changed once, does not recall the time. Anyhow, I replace it today, will see how it goes

 

Something is not communicating in there between the Key Fob and the car. Yes, get a good coin battery for your key fob preferably Duracell or Energizer. OK, 12V battery changed in 2021, to be on the safe side, have it tested at any auto parts store like Autozone, O'Riellys, AAP, NAPA or PepBoys and they can test the battery for you free of charge. If it tested OK, then the batteries are all ruled out.

If your car does not start the next time around, put the Key fob underneath the steeting column,. There is a RIB section and place the key fob underneath the RIB section (on some models RIB section is on the side of the steering column). The car will start.

This video is for a Land Rover Evoque. Land Rover and Jaguar shares the same techonology on all their vehicles. Take Note (Radio Receiver module and KVM module) just in case on your next visit to your dealer.

 

Thanks mate, so far it works perfect after the key fob battery change