Hello all, I have been having a re-occurring issue and it is getting more frequent. My 2012 XFR 5.0 Supercharged just randomly losses all electrical power and leaves me coasting to a stop. It is unsafe to drive for fear of it shutting down in the middle of a merge or something. I have checked all the Power Cables and Fuses. Everything is tight. There is no wear on any wires. After about 5 minutes to an hour I am able to start the vehicle right up and it runs fine but all memory in the system has been reset. Any Ideas? I have searched the other threads and tried those ideas but nothing works.

 

Could be anything from a loose wire (presumably to do with the ignition) to a fault that gets data logged but you'd need SDD to read.

 

How old is your battery?

 

^^^^ this

 

Problem Fixed:
OK so its been a while and I finally found and fixed the problem. I tried everything from buying a new battery to calling the Jag Dealer (who was no help at all).
It started running fine again for a few days then left me dead in the road with no warning.
When I opened the trunk with the key to check the fuses I heard a small electrical actuator somewhere which meant i had power to something from the rear fuse box.
**What I am going to say now is not recommended but I was stuck and frustrated.**
I took my Jumper-cable and bypassed the rear junctions terminals and hooked straight to the top of the front fuse box under the passenger kick panel.
I immediately had power and was able to start and drive all the way back to the house.
After that I replaced the High Amp Fused going from the Junction tot he Front Fuse Box which cost me only $5 online.
Haven't had the problem since then. Not sure why it worked some of the time and then all of a sudden go out.
My best guess is maybe the element was separating when it got hot causing the random shut downs.
I never saw the High Am p Fuses before because they are tucked away in the trunk under carpet further back behind the rear quarter panel.