My car has been in the dealership for 3 days and they cannot figure out why the stop-start does not work. They did 3 software upgrades and several minor fixes but still can't figure it out. It has never worked from day one and I am not unhappy with that. I will tell them I am picking it up today as it would sit all weekend with nobody working on it anyway.

 

Wanna trade cars? I find it the most irritating feature on the car. it isn't even seamless in operation. The buzziness/coarseness I get in ECO or normal mode comes second. I use Dynamic which extends the revs. Otherwise I am happy with a better product than the Germans are producing IMHO
AL

 

Aha moment! There is a small black wire connected to the right side of the battery (the post has 2 screws) and the one on the right screw disconnects the start stop function. The eejit who took the battery charger off the car in the showroom put it on another post and that was not the right spot. So, the start stop works perfectly and I can permanently disable it if I want. Wish I took a pic before I loaded all the stuff back in, including the spare, trunk cover, trunk tray, etc!

 

Well, that confirms what I read elsewhere that the Start/stop could be disconnected off the battery under the trunk rear tray. I might do it myself. It is a bit onerous though as you note to dig out the rear battery and locate the various plug-ins.
cheers
AL

 

Sign me up for disabling the Start/Stop function! "There is a small black wire connected to the right side of the battery (the post has 2 screws) and the one on the right screw disconnects the start stop function." I'm going to try it tomorrow. I don't think the Start/Stop function is implemented well in this car...at least in the the V6 SC engine. I've been in cars that you feel and hear almost nothing when it's activated. Maybe this engine configuration doesn't lend itself to a seamless Start/Stop due to the supercharger? Also...I was going to test the difference in gas savings with/without it but it is so annoying it's worth less gas mileage not to put up with it.

 

Is the wire you are referring to the wire under the bolt to the right of the battery post? It's an orange and blue wire with black heat shrink covering the connector lead. If that's it I bet it had nothing to do with a battery tender but more likely done on purpose for another reason. Didn't I read in another post where they upgraded your software? If that's the wire one should be careful removing it as it connects the +12 Volts to the entire system. If that's the one I will run a jump lead to the other end of the huge red cable the bolt is holding to the post clamp and the post clamp after waiting 15 minutes from when the trunk was opened to ensure the system has stabilized to holding voltage (after any electricity is used....like opening the door or even touching the door handle).

 

Your battery terminal looks different than mine. Mine has TWO posts on the battery terminals and the wire is small gauge, I would guess about 18-20 or so. Yours appears to have only the one wire so I have no idea how yours is set up.

Strangely enough I also did not have the red tag on the plastic tie before and now I do. The wire that is now connected to the battery lug was loose on that screw below that has nothing on it. I am relatively sure the dealer showroom tech MAY have disconnected that wire to avoid stop-start as in the showroom every time someone sat in the car and turned the ignition on it had the potential to start.

 

BMW had the same problem which they fixed for subsequent years. The car would shake when started. The Jag isn't much better. I will disconnect mine too. If it cost me 2 mpg it wont ruin my world. cheers
AL

 

'16 build vs '17 build. Still searching for a way to turn off Start/Stop without the button. My last car required a button push to change it to "Sport" mode....which was really 'normal' instead of ECO....and even after 3 years I would forget to push it after starting the car. Sigh.

 

The one in your pics is the one to disconnect. Simply disconnect it (Use a socket wrench and be careful not to move the main battery post) and simply tuck it away. No more start-stop! Note that the main battery lead is below, so the small wire does nothing but engage or disengage the start-stop. Mine has been off again for awhile and nothing changed. Software updates still intact. Merry Christmas!