My wonderful 2004 XJR fuel pump fails almost every morning. For the last year or so my car often will only crank and not start. Usually in the morning. I put a diode on the fuel pump lead in the boot fuse block, so I can tell when fuel pump is energized. When there is power to fuel pump light goes on. I can see the diode as I taped it to my rear window!! Often when I turn on the ignition no light comes on. Car wont start. If I switch the ignition on and off several times the light will come on. Sometimes after turning on the ignition if I wait up to 12 seconds the light (fuel Pumps) will come on. Something in the car is “thinking” and disables the fuel pump. Could it be the fuel rail pressure sensor? I plan to replace that this weekend. I did replace the Inertia switch to no avail. Got fooled by the time delay into thinking this might be the problems. (long story). There are no codes on the OB reader, but I understand proprietary Jaguar software may tell one more than over the counter reader. No JAG dealer near me. Once the car starts it does not fail, except for once! Sometimes the light will go on for a second then shut off. All other systems on the ignition switch, such as seat belts, do not fail, so I feel is not the ignition switch itself.
Have you tried checking the FP relay? It might be that the contacts are pitted or the terminals into the plug are corroded? I don’t believe the FPR will have anything to do with the problem.
I believe It is solid state and non servicble in this car!
Bummer!
Non serviceable? How about trying a replacement? Surely they can be replaced?
Apparently must replace entire fuse block. $650+
Wow, that has to be the most retrograde step ever 