Hi All
Just picked up 2015 XJ

Is there any way to disable the stop/start function permanently.

I have been turning it off every time I start It.

Thanks in advance for your help.

Ralph

 

Welcome to the forum Ralph,

I've moved your question from General Tech Help to X351 forum. Members here with the same model will be able to help.

Please follow this link New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum to the New Member Area - Intro a MUST forum and post some info about yourself and your vehicle for all members to see. In return you'll get a proper welcome and some useful advice about posting to the forum.

Graham

 

RH913RH, unfortunately, since the START/STOP function was considered as part of the emissions testing and MPG rating, that feature cannot be turned off. It is required to be enabled per federal law.

With this being said, if you know someone with SSD/IDS software, they should be able to get in and disable the feature. But, this would have to be a private person that does this as any professional shop will not be legally able to do it for you.

 

Does it use a separate battery for the stop start like I believe the XF does? If so, what happens if you just disconnect that battery? I suspect you'll get an error warning. But maybe no stop start?

 

Thanks for the info.
I suspected as much since the manual had nothing.
I will look deeper
I was hoping maybe a fuse.

Ralph

 

BritCars, at a minimum, I would suspect that the motor would turn itself off and then not be able to restart normally (ie, automatically). The system may be smarter than that, but I would not be holding my breathe too much. I guess you could try it and see what happens. Just make sure to tape up the lifted battery cable really well to prevent any accidental arcs/sparks.

 

There are two systems used in Jaguars right now. If you have the earlier 2 battery system it's simple to just unhook the second battery.

It looks like the 2016 and up cars dropped the second battery and use just the main unit. That also can be disabled and has.

This is the 2 battery method on a F Type;

https://www.jaguarforums.com/forum/f...attery-146019/

This is the one battery method. May be different on an XJ?

https://www.jaguarforums.com/forum/f...attery-146010/
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All you need is a light foot on the brake pedal to keep the stop-start system from activating.

At first, I hated my 2013 XJ's stop-start system and, like the OP, wanted to permanently disable it. But after being stopped for a long time at several traffic lights, I decided to give it a try. Now, after realizing that I could control its operation by modulating the gas pedal, I really like it. I am amazed that get over 16 mpg in the city with 5.0L and 470HP, which is 3 mpg better than my 4.2L XKR with 420 HP.