Merry Christmas all....
So one of the things I got for Christmas..... Aargh... Was a code that is new to me... P1646... Which I understand to be a fuel pump relay 2 for a model with a supercharger.... Which I don't have.... On further investigation... The dreaded Jaguar Dealer Service supervisor...I have been told that this is the code for a passenger side upstream O2 sensor.... RAs the car is running great.. Always dangerous...I am assuming... Even more dangerous... That it can't be a fuel pump issue. Done a hard reboot... And we cleared the codes and immediately had P1646 pending again... Your valuable insights and proposed course of action to narrow this down would be greatly appreciated.
Brianxj8

 

Just go up to the forum search engine and enter 'code P1646' and you will see that many have been there before you.
It is the upstream sensor on the left (driver) side that needs replacing.
And happy New Year.

 

This code is super common. Here is a link on what to do

jaghelp.com: P1646 and P1647 on your XJ