I replaced the battery in my 2007 XKR 3 months ago. The battery died but it was quite old and I didn't have any reason to suspect there was any problem other than the battery had aged out. The car ran fine for maybe 10 weeks and then it would occasionally have trouble starting. I would hit the start button and it would click like you might expect when the starter or battery was dead. It would start without issue a couple of seconds later and then after a week or two it had greater problems starting with both the clicking and not starting taking longer. I pulled the codes with my relatively simple code reader which returned a U0104 message (Lost Communication With Cruise Control Module). I put it in the shop last week to have it checked out. Initially they couldn't find any problem. The car started for them without issue and the battery tested fine. It stayed at the shop overnight and when they got in the next morning the battery was dead. They tested the starter and the alternator at some point and both tested fine. They pulled codes with their shop machine and got lots of different codes all saying Lost Communication with some module.

They guessed that the battery was dead or there was an electric drain somewhere in the system. I replaced the battery again and the car started without issue. It continued to start without issue and I drove it this morning (it is my daily driver). It started fine but I noticed about half way through my trip that the fan was running after I shut the car off. It was cold outside so this concerned me. On my return the car started acting funny a few blocks from my house. It first sent messages to the dashboard saying the battery was not charging. Then it lost a little power and then the dashboard went completely dark. The car was still running so I drove it the remaining few blocks to my house and it died in the driveway when I slowed down to pull it into my garage. I have a battery charger on it right now just hoping to pull the latest codes.

I assume that all of the Lost Communication errors are due to the battery running out of charge. If anybody has any feedback on that, I would love to hear it.

I am guessing I have an electrical problem. Has anybody seen anything like this before?

All help is greatly appreciated.

Biff

 

Hey Biff. Yes I'd agree that the lost comms messages are due to the battery issue. At first blush I would be checking ground points. Then I would do the same on the positive side. You can have an intermittent ground failure until it does what it did to you as you got the battery not charging message. I suspect cables somewhere. At least that's where I would start given the shop already confirmed the alternator was producing. But it is also possible the alternator is failing intermittently, though in my experience, ground points are my first area of concern.

I've had the problem in the past though not with Jaguar or the benefit of an intelligent message center to give me hints.

A quiescent drain is certainly possible but you wouldn't expect a "battery not charging" message. You may have both problems but the bigger of the two certainly is that the alternator not feeding the battery. Once you get the car running again, testing the voltage at the battery while running will confirm. Testing when the car is acting squirrelly then will tell you if the battery is getting it's 14 volts at that point in time.

If you have Torque pro, it will tell you the voltage output in real time as well.

 

I'll add that I've read a couple of instances here on the forum where the battery cable was the issue but I don't think it's common.

 

alternator going bad.My alternator went out just a week after buying my 2007 XKR back on July 9,2016 back when i had it. Almost $2k to get it replaced at the Jaguar dealership.If mine did that,I know yours not too far behind if yours been working off the same alternator since the car was made judging by the age of it too.For some reason,I think the alternators in the 2007 won't no good,cause when the dealership replaced mine,they said my alternator was shredded.I think when the battery low,it makes the whole car act funny when the alternator not giving it enough charge.It's not gone throw a code for it cause the dealership replaced my battery twice thinking that would fix it and it kept draining it and i'll ride away from the dealership a good 20mins or so and the Jag started making a warning noise like somebody shot a missle at me with a cat suspension error warning on the dash and I was able to pull over into a parking lot and called the dealership and they offered me towing and a couple days later, they found out it was the alternator going bad,and then it took like almost a month to replace it and idk if they were backed up on performing maintenance on other cars.That was the only issue i ever had out of my 2007 XKR to tell you the truth.Other than that,it never gave me any other problems.

 

I went ahead and replaced the alternator/generator 11 days ago. The Jaguar manual refers to it as a generator. The battery hasn't died since. Fingers crossed that the problem is solved. Replacing the alternator/generator was a bit difficult as access to one of the engine mount bolts and the top generator bolt was pretty difficult. Thanks to everyone for all of the helpful advice.

 

if you driving it now daily or when ever you want, and it's no longer draining the battery any more,that means it was the alternator and you fixed it.Hope you back to enjoying that Beautiful XKR😎

 

I drained my bat while cleaning it one day. Charged it over night and things seemed okay. Two days later alternator screamed at me and died. I replaced it myself and it was quite difficult as one of the bolts was almost frozen. I read shortly afterwards that there was an advisory on charging battery, 2007~2008, would cause alternator damage in some cases. Since I was charging with big, old charger this may have shortened alternators life...dunno. All is good now.
wj

 

i knew it was a problem with the alternators on older models since that's the only thing that ever went bad on mine

 

In the (few) times I've had to charge my battery, I've always removed both battery cables and charged the battery disconnected from the car (in situ). Most chargers provide brute unfiltered D/C at their output, which could compromise delicate car electronics. Just being cautious...

 

These cars are ok with such DC.

Note where Jaguar say to connect, though.