I ended taking my car to the dealer (Newport Beach Jaguar) to diagnose the SIM reader issue; it turned out to be a defective Telematic Module (part# T4A14249) which was replaced under warranty. Now my connectivity to 4G networks is back.

 

I had the Mint mobile SIM in for a month or so and it kept toggling on/off to get the data and then would only go to 3G most of the time. Then I recalled this thread about changing the settings which above was related to Google Fi. Turns out that similar applies for the Mint SIM, I followed the instructions I found here and used the "alpha" name for the setting instead of auto select, now it comes on to 4G. Will have to keep a watch and see if it sticks.
https://community.mintmobile.com/you...pn-settings-27

 

Did you need a Mint monthly plan for the SIM to work?

 

It is a pre-paid SIM, you can set it up for pay in advance to have it active, otherwise I think if you don't pay for that month, then your data will be off. It is not a consumption plan.

 

Same for me; same issue, same part replaced (Telematics Module T4A14249). The index card solution posted above suggests that some of the telematics modules have weak springs for contacting the SIM card contacts.

 

Maybe 4 times in 18 months I’ve had to eject and reinsert the SIM to get connectivity back. Will mention this at the next service.