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I know that to disable the start/stop "feature": the secondary battery is typically disconnected. In my new-to-me R, it was already disabled, which I'm happy about, but... I was looking at how stuff is connected around the battery, and was surprised to see not only the secondary battery in-place, but it appears to be fully connected. Just for my own information, how do you think the stop/start was disabled if the battery is present and connected? I have not checked with a meter to see if it's charged, so I suppose one possibility is that it either failed, or someone disconnected something somewhere that keeps it charged.
On a related note, I saw this module next to the main battery with a red and green illuminated light on it... what is that module and what do the lights mean?
Lastly, right next to the flat-fix bottle is a Styrofoam holder for... something. Anyone know what? The Owners Manual doesn't mention the latter two issues.
That module with the red and green lights looks after-market to me, my MY 2015 has no such thing and I have never seen one before in any of the many battery compartment pics on this site.
I suspect it is what the previous owner has used to disable the SS system.
The normal easy and free way to disable it on an early model F-Type with the two battery system is simply to disconnect the black cable which runs from the negative terminal of the secondary battery from where it bolts to the floor of the trunk.
The secondary battery is over on the other side of the trunk (RHS or passenger side in the US) tucked up against the rear (it is showing bottom left in your top pic) and I can see that cable bolt down point in your top pic, about 1/3 the way up from the bottom of the pic just left of centre.
That module with the red and green lights looks after-market to me, my MY 2015 has no such thing and I have never seen one before in any of the many battery compartment pics on this site.
I suspect it is what the previous owner has used to disable the SS system.
Not sure what it's for, but that's definitely aftermarket. Disabling ECO seems like as good a guess as any.
Full disclosure, I'm an electrical engineer. I asked because I thought that the module was something that some or all of the Rs come with.
So I got curious and looked at it again. The first thing that got my attention in a big way was that when I touched it, the red and green LEDs lit up! I confirmed that the two wires go directly to the battery, so it's always powered, and the two short wires on the same connector go nowhere... so, yeah, sort of a mystery. Pulled the module off its Velcro mount and on the back made everything clear. Turns out what I have in the back of my car is a GPS tracker! I suspect that one of the previous three owners added it and then forgot to tell the next buyer. Pretty sure the NSA isn't after me... probably. Anyway, I unplugged it, so back to blessed anonymity.
Full disclosure, I'm an electrical engineer. I asked because I thought that the module was something that some or all of the Rs come with.
So I got curious and looked at it again. The first thing that got my attention in a big way was that when I touched it, the red and green LEDs lit up! I confirmed that the two wires go directly to the battery, so it's always powered, and the two short wires on the same connector go nowhere... so, yeah, sort of a mystery. Pulled the module off its Velcro mount and on the back made everything clear. Turns out what I have in the back of my car is a GPS tracker! I suspect that one of the previous three owners added it and then forgot to tell the next buyer. Pretty sure the NSA isn't after me... probably. Anyway, I unplugged it, so back to blessed anonymity.
That's one mystery solved but we still haven't solved the other one, why your SS system appears to be disabled.
It is well established that if either battery is poorly the SS system doesn't work so the first thing I would check is the health/charge of both batteries.
Whatever you find I would remove the second battery anyway which permanently disables the pesky SS system with zero effect on anything else.
I changed my main battery after 7 years, but at that point, the SS battery was already dead. I’m guessing yours is too. I left it in there for a while, then finally removed it to save a bit of weight.
No battery is the same as a dead battery - when I start the car, the light on the ECO button comes on briefly, then shuts off.
The SS system is very poorly designed and fails often. I bet if you hook up SDD you will find SS error's. Brutal one of our factory tech's has stated the system is failure prone and it's best to let it be when it stops working. I have a 2014 XJR. The little battery went bad and I replaced it. SS worked off and on for a while then I noticed that no matter how I drove the car there was no SS?
Later I hooked up my SDD for something else and the car threw a SS error code. I have no plans to fix it.
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Because I just got the car and haven't spent much time in the R, maybe I never noticed before, but the ECO button does come on and stays on after startup, but the engine stop/start doesn't work. That's fine with me, and as suggested, I'll be removing the likely-dead secondary battery, but surprised the ECO light comes on even with a dead battey.
The light indicates the system is potentially active. Even when it's "working" the stop doesn't always kick in - it depends on a number of criteria being met, as listed in the handbook.
To finish this thread, I checked the voltage of the secondary battery and it was around 10.2V, so it's bad and/or not being charged, so the battery, hold down bracket, and cables have been removed. Started the car just to make sure no warnings came up and the ECO button lit but went out after a couple seconds.
Rear battery area questions
