New here too and am hoping to find a solution to this terrible feature as well. It should at least default to the disabled state. I personally don't like the feature for the following reasons:
1) Each time you turn off the engine, the internal temperatures spike up.
2) Each time you turn off the engine, the oil pressure is lost.
3) Finally, and it is a long stretch, but starters do fail. I would rather it fail in my garage when I first start the car than when I am sitting in stopped bumper to bumper traffic on the freeway.


I personally don't believe that it saves any significant fuel and it is more of a marketing gimmick than anything.


Is the second battery installed just for this feature? I don't even know if my 2015 has one? Thanks if anyone comes up with something.

 

How I did it for a 2016 XJ...
Remove the trunk floor exposing the battery, spare, etc.
At the back end (towards front of car) of the battery is a thin, rectangular, silver module attached to a bracket. Several wired plugs are attached to the face of this module. The small black plug closest to you, with the SMALL GAUGE colored wires, can be unplugged. Secure this disconnected plug.
When you start the car, after about 30 secs., the "ECO OFF" light will illuminate in your dash.
No more stop/start, and no problems for me so far! Let me know if this works for you too, or if you notice any other issues...
Good luck!

 

THAT'S how you do it!!






According to my dealer, it's not a battery, rather a capacitor. Either way, yes your car has one, and that's what it's for............and it's also the "thingy-mabob" that you disconnect, to defeat the inconvenient as hell, eco-start.

 

Works perfectly! Thank you!!!