I drive a 2010 XF 5.0L. Hoping someone can help.

So I tried starting my car, pushed the break pedal down and pushed on the start button. All I heard was one click and the car wouldn't start. All the lights came on without any problems. I did notice the break pad was hard to push in too. Anyways, I got someone to jump my car and the car still wouldn't start. I let it rest for about 15 mins and tried starting and it works so I drove it home, took the battery out, and got the battery checked at autozone. Autozone said it was a bad battery so I bought a new battery at Costco and installed it. Afterwards the car started right away.

The next day, same issue. My car is not starting, only hear 1 click, and all the lights came on. I took the new battery out to get it tested (just in case it was a lemon) but battery came back fine. Not sure what the problem could be now. I read that it could require a hard push down on the pedal to start but that didn't work. I checked the fuses and all seems fine. Now I see a low battery warning message on my radio (attached picture).


Can someone tell me how to troubleshoot this?

 

It sounds like something is remaining powered "on" after you park the car and draining the battery overnight. It used to be pretty simple with old cars, either the door was left ajar and the "dome light" was on all night or the ignition switch was worn and leaving the power on to the accessories or a diode in the alternator was bad. With today's modern electronics it could be any of a hundred things. The general diagnostic procedure is to connect an ammeter, look to see how much current its drawing, then start pulling fuses to see which fuse makes the current drop significantly. I'm sure there's probably more specific testing procedures for the XF and one of our tech experts will come along soon.

But the first thing I'd check is if you have any phone chargers or such plugged into the car. The power to those ports "should" cut off a few minutes after you've shut off the engine, but I suppose something could go wrong there, maybe a bad charger causing feedback that interferes with normal operation. As a general rule in diagnosis, always check the easiest/cheapest fix first and unplugging any phone chargers would certainly be the easiest. Another thing to try is to make sure you lock the doors overnight, even if its parked inside your garage. Its sort of the difference between powering off your laptop computer vs putting it in "sleep mode". When the doors are left unlocked, it doesn't fully power down, but some systems stay "booted up", just in power saving mode because it expects the driver is coming back soon. When you lock the doors, it knows you're going to be gone awhile and shuts down all but the security system. Leaving the doors unlocked overnight still shouldn't drain your fresh new battery, but locking the doors might prompt whatever IS draining it to shut off and buy you some time to get it diagnosed and repaired. I don't know where you are located, but those are two things you can check or try tonight.

 

Thanks for replying. I just checked and noticed that nothing was plugged into the usb and ensured that the door was locked; all the lights powered off. Can you think of anything else?

 

Even if your battery is suffering discharge, you should be able to jump start it

What happens when you press start and the car just clicks. Does it come on into accessory mode (dash comes on, radio and fan etc?)

I'm pretty sure what's happening is that the pressure switch in the brakes is not being triggered. When you start you have to hold down the brake for safety and the car starts. Else with no brake it goes into accessory mode. In your case it doesn't think the brake is being pressed

A few possible causes
- most likely the brake vacuum boost has run out. When you park the car and turn off the engine, do you keep your foot pressed down on the brake or do you take it straight off? If you keep it pressed down it uses up the boost and you have to depress the pedal manually which is very hard...
- possible the brake pressure sensor switch is faulty but that's not common.
- else it's electrical gremlins and would start with fully charging the battery and monitoring its voltage

As an experiment when it happens try really stamping hard down on the brake pedal and pressing start. That should make it work

 

I don't hear the fan but dash comes on, radio screen comes on but no sound and then it shows a low battery symbol. No fan. I tried to start it again and got the same result but this time I hear a small pop and the light seemed like it dimmed a bit? Pretty sure I heard a small sound but this is when I am connecting a code reader to it too.

I always step on the brake when I park the car then I take my foot off.

I thought about fully charging it somewhere else this time, like autozone instead of o'reilly's again. Maybe I'll tell them to let it charge for awhile (few hrs). Last time I tested this new battery, o'reillys told me the battery was good. I think it was charging for about 1.5-2 hrs? Is that enough time? I also tried pressing hard down on the brake pad and it still didn't start. I'll try again and let you know.

 

Certainly sounds like battery is low and you should fix that first. Then you can see if other issues. On a standard trickle charger for a car battery it could take 12-24 hours if it's really discharged. Do that and measure the voltage across the battery. Then see if it starts reliably

 

Hi BritCars,

If I bring it to an auto store to charge, would it require 12-24 hours to charge? Odd that this is happening with a new battery...

 

New batteries are often not fully charged. And as someone said above there could be some parasitic drain so that once it's in the car it's constantly running down

Best bet is to buy a charger - about $50. Plug into power and connect to battery/ground and leave it for a day
It is also possible that your battery is bad. I got a new one on the XF about 18 months ago (prior one lasted 6 years). After a couple of months I got low battery notices constantly. Store 'checked it' and said it was fine but issues continued and I couldn't get it to register full charge so they replaced it on warranty. New one is perfect

 

Jump starting doesn't always work when your battery is fully discharged. It depends on the size and state of the battery in the other vehicle. If the other vehicle is a big v8 diesel tow truck with 1,000 cranking amps to spare, it should jump start fine as long as that is all that was wrong. But if the other vehicle is a 3cyl 10:1 compression Ford Fiesta with a puny little budget battery from Walmart that's already four years old and half discharged itself, then it won't be up to the task of starting your 8cyl 11.5:1 compression Jaguar.

The auto parts store will likely have a 40amp charger that'll do it in under an hour. But its unlikely to be the fault of the battery.

Your story sounds like something is draining the battery overnight. You get yourself an ammeter that looks something like this, clamp it around the positive battery cable, set it for DC amps, make a note of how much current its drawing at rest and then you start pulling fuses and relays one at a time. When you find the one fuse that makes the current go down by like 80-95%, you've isolated at least the circuit/system that is responsible. From there it's tracing wiring diagrams and testing individual components which may be best left to a Jaguar technician. But then again, it could be something as simple/cheap as a stuck relay.

 

I went back to Costco and swapped the battery I bought 5 days ago with another new battery, installed and still the same problem. At this point, is it really the battery still? How about starter or alternator? Does anyone know where the starter and alternator are locate? Can someone provide a diagram on how to access and remove them?

 

Do the test you quoted.

Also test for a current draw via the voltage across each fuse - use web search there are even youtubes about it.

 

posted in error

 

Just a thought,

I had an issue where my 2009 xf would search constantly for my cell phone. I noticed if my phone was left within 50 feet of the vehicle, it would be the cause of draining the battery if I didn't drive for a day or more.

Once I began keeping my phone on the other side of the house, the situation stopped. The electronics for the phone maybe under the passenger seat. Tough to access without removing, but maybe disabling it might help.

I think this is a less prevalent story, but I know the feeling and think sometimes it's good to check everything under the process of elimination.

Good luck

Dallas