I agree, that the "low battery" messages might be a bit erroneous...




The evening my wife and I picked up our '12 XJ-l, we were in the showroom, with the doors open, as our sales rep was going over some of the features of the car, and the "low battery" warning message came on.




This was on a brand new car!!

 

I agree with post which says the owner LOCKS the car, even while it's in the garage.
I left my 2012 XJL-Portfolio w/ only 7400 miles unlocked in the garage the first night after I purchased it this past November and the next day I saw low battery warning. I then began locking the car and have since not had ANY problem.....just my experience.

 

An old thread I know, but that last post may be relevant. I just got back to my car after being away for 3 weeks ('13 XJL) It started fine first time and drove well. No dash lights on at all, other than low brake pads. Then I plugged in my phone charger through the USB port. Just like when I first got the car it can never charge my phone; instead always staying at about 1%. It says it is charging the phone, but never goes above 2% - i.e. only providing a very weak charge.

I kept driving for about another hour and warning lights steadily started coming on. First it was "Charge System Trouble indicator". in red. Then it was suspension error (in yellow). Then the dash screen went out or at least started flickering. Then it said "Stability Control System" fault in yellow. Then..., other warning lights started coming on, including gearbox fault. I limped the car home - as by that tme I was only 100 metres away. Once I turned it off it said something like turn back on due to low battery, but it would not start. I waited 5 minutes and went back out and it started normally and was fine, and I could drive it forwards and backwards a little bit - no problem. Then the Charge System Trouble indiator came on again and at that time I was no longer using the USB port for my phone.

Here is my amateur thinking - please feel free to comment / advise... Other than a failing alternator, given that in the 2012 model year the XJ's had a weak charging system (my car was manufactured late 2012 - relevant or not?) AND given this car has never charged the phone properly (baffling, until now perhaps...) - could it be that the charging system is inherently weak on my car, and that the simple use of the phone charger (while the AC was running - I always need it on here; it is hot !) means that this was enough to have a battery induced set of systems failure? (or only if the alternator is weak?)

Other than that or failing battery (but my car started first time after my being away for 3 weeks), or the possible failing alternator, does anyone have any ideas what could be the cause of all the warning lights and dash failure? Many thanks and much appreciated...

 

I came back to the car this evening, and it started first time and no warning lights.

But..., the warning light to please restart due to low battery came on after I turned the car off.

Any thoughts...

 

Nearly all of these types of problems (at least on modern Jags!) are caused by a battery which is less than fully charged and/or getting a bit old and weak.
Even if the car started straight up after being left for 3 weeks the battery could now be dodgy.
How old is the battery in the car? If it it still the original it is now over 10 years old and well due for replacement.
If the battery is not that old (say less than four years old) then it could possibly do with a recharge, the CTEK brand of battery maintainers/tenders is popular around here. It is good practice to hook up a CTEK or similar whenever the car will be left unused for more than a day or two, I hook up my battery tender (not a CTEK but it works great) almost every time I leave the car in the garage and my original battery now some nine years old is still going strong.
Maybe the BMS (Battery Management System) is acting up and needs to be reset?
Easy to do, just disconnect the battery for a minute or so then reconnect it. The easiest and best way to do this is to disconnect the earth/ground lead from wherever it bolts to the floor or side of the trunk/boot, dunno where this is on an XJ but on most modern Jags it's on the floor and held down with a 12 mm or 13 mm nut, just follow the thick black cable which runs from the negative battery terminal.
Do this disconnect/reconnect reset then put the car on a tender overnight, this has worked to fix battery and electrical system problems on hundreds if not thousands of Jags. Worst case scenario buy a new battery and fit it, on a 2013 XJ you will need an AGM.

 

Excellent information, thank you.

 

Have to agree with OzXFR strongly! We have seen a wide range of strange problems fixed with a new battery.
So don't discount that as your problem.

Jaguar must have taken all the electrical problems to heart because my 2014 XJR has had zero electrical quirks. I am changing my factory battery this month and it's now 10+ years old! But nothing is wrong with it I am just getting nervous! I have left the car for 6 weeks at the airport and it started right up with no dash lights. I have never had any low battery warnings and I never lock my car. The keys are also stored within about 20' of the car and this has also caused no problems.

So if you have an earlier XJ I also recommend using a maintainer at all times if possible. It just prevents a lot of electrical problems.
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By the sympthons its sound that you have weak contact on battery terminal or engine to chassis.

 

Thank you Vasara and Clubairth... - appreciated.

It started fine this morning and so I turned off all unnecessary electrical sources I could - and drove it to try to charge it; and that worked quite well (no major dash lights etc.), but after a bit the red, electrical "Charge System" fault came on again. So, I agree and plan to examine those connection(s) to ground / chassis / engine exactly as you suggested and if needed repair / replace, and also test the battery. Then perhaps a new battery, or not if ont needed. I will also purchase a CTEK battery maintainer / charger, and use that.

My other problem... ...is that it is such a nice place to BE that I just find excuses to drive it and the gas I am spending is embarassing. I'm getting close to $30 a day...

 

does anyone think leaving USB phone charging cables just plugged into the car (not connected to phones) would affect battery level at all?

 

That is an interesting point, particularly given my USB port would not charge a simpe cell phone hardly at all - and, come to think of it my cord is still plugged in...

 

USB1.1 and USB2.0 ports are rated only 480mA max output, so you don´t get much out for modern cell phone. Better to have cicared lighter adapter what can give 2A - 3A depending model.
Plain empty charger cord don´t consume anything. No effects for vehicle battery level. (output will be cut off after 10min of shutting the engine anyway)

 

No, there's no draw when nothing is connected. It's just a cable. There's no transformer.

 

Interesting because on the F-Type forum they recommend disconnecting anything attached to the car.
Including code readers using the OBDII port. Several have commented that leaving the phone connected also causes problems?
Not sure how or why.
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Sure, an device on ODB port can cause systems do not go to sleep. It also can be that device what are not regonized by infoteinment operating system (QNX) can prevent it shut down. However, plain cable are not reginised at all by USB host.