My 2005 XK8 has suddenly developed a sudden power loss problem. The car goes completely dead. No click, no dim lights, no access to trunk, no door locks, nothing. Futz with the turn signals, key (starter), etc. nothing. Just as suddenly, the warning lights come on, the steering wheel extends and I am able to start and go. As of this time, has only happened twice (over the most recent three-day period) when car is sitting (once for 5 minutes, the other overnight). Has not happened while driving... thank God. (Interestingly, although I lose my seat memory, my radio channels are not lost.)

Battery has been checked 100%.

Ongoing issues that might have some bearing...
• Windows have on occasion, lost their memory.
• On occasion, notice sputtering in dashboard lights
• Radio has, again on occasion, lost memory (channels)

All, I believe, indicative of a power loss somewhere.

Any suggestions would be greatly appreciated.

 

Check the connections to the main junction box in the luggage compartment (arrowed in blue):



Connections have been reported to come loose. Also feed cables from the battery can deteriorate.

Graham

 

Will do thanks.

 

New update... Notice it corrects itself when I close the drivers door (not sure if it's the slamming of the door that jars something loose or some connection related to the door. Also noticed that the symptom has changed. Now I turn the ignition on and I get clicks (typical of a dead battery), the steering wheel extends outward and then when I try to restart, it works fine. Still no issues once I am running.

 

+1 to Grahams suggestions. The battery cable can sometimes be fixed by sqeezing the crimp in a vise.

Also each fuse box has a battery feed (a heavy cable) that is fastenend with a nut. These have also been known to come loose. Always disconnect the battery first before putting a wrench on these.

 

As Steve(WhiteXKR) says the +ve lead battery terminal crimp is a good suspect.
A clue can be that it gets hot when the car's running.
The other thing to do is follow the -ve lead to where it bolts to the body, pull it apart there + really clean it all up.
As Graham + Steve say 100% a bad battery connection somewhere in the boot.

 

What's with that red wheel!

 

I hsd a simular problem that was solved by cleaning the contacts on the door harness connector and ensuring it was sealed properly.

 

Only us Brits have the right to red wheels. Sorry, not for ex-Colonial markets.

(actually it is a little miserable space saving low speed cheapskate spare wheel in red so the cops can see it)

 

After all the great input, did some more investigation and found the problem. It was, as many mentioned, the fuse box battery feed. now running like a charm. Thanks to all. Booya!

 

Thanks for posting the results. We all learn that way.

 

It's the alloy Space Saver spare wheel supplied with 'R' performance spec vehicles on 20" wheels. Vehicles with 18" wheels have a black steel Space Saver.



The steel wheels retain the recommended pressure for long periods but the alloy wheels seem to drop 5 psi or more in a few weeks. Worth regular checks for anyone who has this type.

Graham

 

Graham,
You've complained about pressure loss before and I've dutifully removed all the cr*p in the boot to get to our little Red Lovely - never a change in pressure.

 

Similar problem. Just got the R back from Jag, all was well until I pulled into the drive this evening. Experienced complete power loss and could hear a ticking sound from under the bonnet. First thing I checked was the trunk mounted junction box. All seemed tight. The minute I touched the battery ground cable the ticking stopped and power was restored so this sounds like it may be the crimp issue. However, the windows, will not do there roll down then up thing when closing the door. They go down only. If I continue opening the door, eventually they are all the way down. This happens on other cars and the solution is usually a reset procedure. Is third the case on an XKR and if so, what is the ECU reset procedure?

 

Roll the window up and hold until you here a click. Then down and hold for the click, and again up and click. Should be reset now.

 

Thank you.

 

You guys are life savers. I have started my XKR thousands of times and never a problem aside from having to lightly jiggle the starter relay under the hood like 3 times in 3 years, and a bad battery once. Today I went to crank it and nothing. Had everything else, but no starter. ERR showing on the climate control. Wrong part installed on the annunciator. I came here, seen the RED TIRE, popped the covers on the BATT STRIP, took a 1/2" wrench and checked those connections. WHA-LA! FAST IDLE Check engine light is on. Turned it off then back on without starting, did my windows, and the throttle, back off and recranks fine. This is THE PLACE FOR JAGS.