2003 xjr-r1

Car is otherwise running fine, but with an undiagnosed suspension fault for the past four months.

I go to the car in the driveway and it is electrically dead. The keyfob won't work, the seat is dead, and nothing happens when I turn the key.

I go to the trunk and open it. I pull up the carpet box that covers the battery and fuse box. As I am pulling up the carpet, the car comes to life. The power is restored.

I look carfully for any wires that I have brushed with the carpet. Nothing is obvious. The harness seems intact. I go for a drive. The battery is fully charged.

During the drive, I lose full electrical power for about 1 second, requiring a restart and radio code.

I go back into the trunk and further inspect the harness. Nothing obvious. No probems with the car for two days.

I think we are probably having a problem with some sort of relay or power to a relay that shuts everything down. Does anybody have any experience with this type of problem?

 

John

Start with the Batt. Give the posts and clamps a good cleaning. After that post this problem in the General Tech Help area. If you can source a Batt for a few days, say from another car, you can eleminate the Batt. itself. Be warned, it's a back breaking job.

There are some major power distribution points that can be checked with a volt meter or test light if you can get to them before the power returns.
On my car there is a power dist. box adjacent to the batt. that bares looking at. It's prone to water damage I hear.

Stay on it John. You can't be driving around with such a high pucker factor. Keep us posted. I have an idea it's going to be real simple and interesting.

 

Would seem to be a high current/high resistance issue. Loosen and tighten all the major points: battery, 250A fuses, cables to engine compartment. One on each side.

If that does nothing start looking at the main power relay to the ECM. Swap it with another relay. Most of the relays in the car are the same.

 

It's British. This is normal. It's part of the "experience"








Sorry, I couldn't help myself.

 

My 1998 had the same issue. I cleaned the battery terminals as suggested here. Removed and cleaned the chasis ground from batt to frame. Cleaned the ground strap from the chasis to the engine block(under the car, near passenger footwell iirc,) but where I believe the was in the engine bay, under the storage area on the passenger side near the windshield. The positive cable makes a connection there. I cleaned and re-assembled it. No problems for 3 or 4 years now.

 

Followed all of your advice and found packrat damage on the leads from the left rear CATS shock. Fixed the wires, back in business. No problems so far.