I have for some time, over a year, getting sperotic error messages during start up and/or after running for some time in my 2004 XKR. These messages were related to "disk break problems", "rear light issues", and "non functioning speed control". These messages bothered me as the Texas state inspection was coming up in a month and I was more immediately planning an extended road trip.

i scoured the Jaguar Forums website and came away with the most probable answer being that the age of the battery was causing these error messages and needed to be replaced. The battery was a do it yourself solution and certainly many times cheaper than the local Jaguar dealership. So I installed a new battery to replace the 7 year plus old battery and two days later began my road trip of some 4000 miles.

After replacing the battery the error messages did not immediately go away but over the following week they became less frequent until they ceased all together. Since then, approximately a month, I have not had any error messages and with one exception the jag performed flawlessly. It also passed the state inspection with flying colors. All I can guess is that the battery must maintain a 99.9+% charge to keep the on board CPU from freaking out and it took several days for the new battery to establish this charge level.

The one exception i referred to was that it started to intermittently produce a humming sound from what seemed like the trunk area at one second intervals. This sound only occurred when the top was down and then on an intermittent basis. This sound has since gone away. All I could think of was the hydraulic pump assemble (replaced a year ago) or the fuel pump, if it is located in the back, was causing the noise. I don't know what would be worse on a road trip, the fuel pump quitting in bug tussle U.S.A. or the top stuck down in a thunder storm.

As stated the sound has since gone away but would be interested in any comments from members regarding this potential problem.

One final note. If you ever get the chance drive the Smoky Mountains, Blue Ridge Parkway, Shenandoah Skyline federal park system along the ridge line of the Application Mountains! If at all possible do it in the Fall and most definitely in a rag top. This 450 mile mountain drive and the XKR were a match made in heaven. It takes awhile as the posted top speed is 35 mph the whole distance with literally a 1000 hair pin curves along the way.

Cordially

 

Rear light issue and non functioning cruise control are related. My 05 had these at purchase and it was a non functioning red rear side marker light bulb. Changed the bulb to erase the problem. I wouldn't trust ANY car battery past 5 years so changing it was money well spent. I have no idea what the buzzing noise would have been?

 

You may at some point want to remove the rear wheels and check the wheel speed sensor tone rings, you may have one loose or damaged.

BRP - Great ride but on our Yamaha FZRs it was impossible to do 35 ;-)

 

Hi ricki ticki,
Good post and well deserved outcome. There are countless posts on the JaguarForums about tired or failing batteries and the warning msgs or faults that can turn your instrument cluster into a very pretty Christmas display . . . all flashing lights in eye catching ambers and reds!

Perhaps more prone, and therefore better reported on the S-Types, but the XK8/R and XJ8/R can be equally afflicted, as can most modern, highly sophisticated electronic control systems in similar vehicles. Perhaps less well known, but universal, is the prevalence of buying and fitting a brand new battery . . . and finding that it is not fully charged!

Hence your finding that, despite replacing your dying battery with a "new" one, it took some time during which your car was trying to fully charge the battery . . . and thus, finally, wipe away the tears. Years ago, "new" batteries were measured, shop charged, re-measured and only fitted once fully charged . . . nowadays, we assume that because it's "new" it's right to go. And that aint so!

The sole determinant is the measured voltage . . . 12.8V is great; 12.6V is probably OK. Of 3 "new" batteries I tested recently, they ranged from 11.9V to 12.4V . . . more than enough to start the car, but not enough to convince the Jaguar ECMs that all was well. However, once fully charged, problems disappear . . . no, not magic, just logical and predictable physics.

Cheers
Ken

 

A couple quick follow ups. First thank you for your responses, they are greatly appreciated.

Thank you jamdmyers for your comment on the speed sensors. I will start by looking into them on this forum. If truth be known it was quite difficult not to give the jag its head on some of the curves. While traffic was quite light, a real blessing, I would estimate that one of every three vehicles that I saw was either a motorcycle or a motorbike.

For cat_as_trophy when I am on the computer, which is quite often, my default internet radio station is Golden Days Radio (95.7) out of Melbourne, which I guess says something about my age. Also thanks for confirming my suspicions regarding the battery voltage.

Again thanks to all of you for your comments.

Cordially