I am currently on vacation for several months, and I have a family member who is starting my 2011 XF once a week for me to keep the battery fresh, circulate fluids, etc etc..

The first few weeks of my trip, no problems at all, my family member would using the keyfob, unlock the car, start the car, let it run for 5 or so mins and shut it off.

On the 3rd week, when they went to start the car, no response from the keyfob. So I suggested they go get my spare keyfob try that (the odds of 2 keyfobs with essentially new batteries being dead is pretty low), and same thing. no response from the car.

So using the keyblade, I had them manually unlock the car, and also the trunk, so they could check the battery, which btw is less than a year old.

For reasons I can't fathom, the battery was "dead". So they pulled it out, charged it fully and put it back in the car.

Unfortunately, this didn't have the expected results of returning the car to normal, instead, it caused to horn to honk continuously (alarm system?) and the emergency flashers to go off, as well as the car still won't start (shifter knob won't raise, etc etc).

BUT, they if they then pressed the emergency flasher button inside the car, it will stop the horn, yet the flashers will still continue to flash, and nothing else works.

Any thoughts on what this weird combo of symptoms is? Is it possible they did something incorrectly when putting the battery back in? Why would a basically new battery (Less than a year old) die after only a few weeks of non-use? Wouldn't the starting it weekly and letting it run for 5 or so minutes kind of charge up the battery from week to week?

Is it possible that taking the battery out of the car, charging it and putting the same battery back in the car has severed the link between the car and the battery, so the battery needs to be re-registered again?

I'm at a loss as to what suggestions I can give them to troubleshoot this further. Would a jumpstart be the next thing to do? It was running fine before I left for my trip.

I also have a jaguar specific code scanner, but I'm not sure if that would be helpful in this situation.

Appreciate any suggestions you might have.

Thanks everyone,
Nick

 

I don't know how to fix this but I vaguely recall that there have been other threads with the same problem and something about the BCM. Somebody will chime in shortly I'm sure. But no, just running the car for five minutes at idle is not sufficient to recharge the battery. I spread my mileage over several different cars so none get driven very many miles. I now normally keep them on CTEK maintainers when not being driven, but I have in the past run into the issue. I'd make several short trips in one car without plugging it in for a month and then have to connect a regular 10amp charger, it'd be down 50% or more and charge for three or four hours. You've got to get it on the highway and put some miles on it at cruising rpms to top up the battery. I don't know exactly how far or how often to recommend, but I know there's been a few occasions that I didn't do quite enough. Maybe have your family take it on a 20-mile trip down the freeway every other Sunday.

 

I would remove the battery from the car, get in bench charged & then load tested.

 

He would have been far better off to actually drive the car 30 minutes or more. The 5 minutes idling really does no good. You need to exercise the car and that means the entire car. Transmission,brakes,suspension, AC system all need to be operated and of course keeping the battery charged up.

Listen to John Williams above!
Report back with what you find.
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Hey everyone,

Thanks for the info. I.. wasn't aware it needed that level of exercise.. so that's on me. but, learn something new every day

I will have it taken to my mechanic, as the keys might need to be reprogrammed, and if necessary swapping out a battery.

Thanks for the tips / advice.

 

turn on and off of car doesnt charge the battery, instead you should drive few miles so the battery gets charged. If you are planning to keep car idle for long ask the electrician to make a switch for turn on and off batter connection. Else better remove the battery cable you just need to disconnect the negative terminal. lock manually and unlock manually and plug in and use the car. This will keep battery alive.

To sort out the issue once the battery is charged, try scanner reset option and drive the car to see whether all errors are gone.

 

I would NOT put a battery switch on the car! Listen to Phil above. Many guys keep the car on a charger to head off problems. CTEK is the most recommended brand and a simple search will show how they hooked it up. I think it would be well worth it because of how your using the car?
This is a common problem and even Jaguar has released a battery Charger Hook up document. It's for the XJ but I think it could be used on any Jaguar.

Nick do you have any updates?
Even with charging the battery it might need to be replaced.

Again as Phil posted above the XF has a strange problem sometimes if the battery is unhooked. We don't have enough information from you yet but be aware you might have problems with your junction boxes or sometimes they are now called BCM (Body Control Module). It normally affects the central locking system so I might be wrong?
See the TSB I have attached.
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