Getting to grips with my lucky dip XKR with Restricted Performance. Had the local Jag agent check out the DTC fault codes which indicated the second fuel pump. This was what a specialist had told me already, so now there is confirmation. Looking at the relay for that pump I discovered that pin 5 had been shorted out to ground, by the previous owner? This little white wire had been quite neatly added. This probably allowed the car to run In RP mode.

So now to find out why there is no signal to that pump relay. It seems to be the main ECU after all, even though this is surprising for a unit that is supposedly reliable.

But the diagnostic report reads 'Engine control module {01 DTC} P1671 No information available'

 

That's a very neat little fix someone has added to get the car to run. The code is the ECU detecting there is a problem with the relay coil circuit - it either is seeing it as shorted or open circuit. I would unplug the relay, unplug the harness at the ECU end and check the resistance of the control wire at the ECU harness, first as open circuit at the relay end (i.e. relay removed) then when grounded (ie short the relay coil pins at the socket). I don't know if you have already done these checks. By the way, you also need to make sure the +ve connection to the relay is getting the correct battery voltage, ie no dirty or loose connection. Test this under load with the relay on.

Your only other option is to try a different ECU, but you will need to do the immobilisation setup before you can start the car.

One last thought - what happens if you remove the extra white wire that is shorting the relay to ground? Does the P1671 go away?