I pulled P1646 code off my Jaguar XKR convertible vin number :SAJJA42B2YPA07837
I am confused as one source says to replace # 2 fuel pump relay, and the other source say to replace right up stream oxygen sensor
Any help on this will greatly be appreciated

 

What year is your car?

I had the same code on my 2002, and it wasn't the pump, it was the oxygen sensor. The diagnostic manual was incorrect.

The tell-tale is if its a fuel pump you will get a restricted performance message too. You can pull your fuel pump relays one at a time and start the car to test that. correction I don't think you need to start the car, I think youll get the restricted performance by pulling relay(s) and just turning the ignition on.

Much more detail in my thread on the subject, and a bit of guidance on how to replace that sensor as it is in a barsteward of a location, but easier than a fuel pump!

https://www.jaguarforums.com/forum/x...d-dtcs-276088/

 

I have had the same code show up multiple times on my 2002 XKR and that was after all O2 sensors were replaced.
I ran the data stream on my phone app and it looked fine so I figured the problem was intermittent.
I believe it was caused by the connector. I opened the connector and saw nothing wrong but cleaned it anyway and put it back.
No codes for a few days and then it came back. I went through this 3 or 4 times with same result each time.
Finally I decided to leave the connector hanging instead of clipping it back onto its bracket.
That worked, No more 1646 codes since then. I think it was caused by vibration of the connector.
Might be worth trying that before you buy new parts.

 

I think the confusion arises from the fact that the AJ27 was introduced on the XK8 the year before the supercharged cars go it. So there was a period when AJ26 engines and AJ27 engines were in use in the same model year. That confusion seems to have spilled over in to the documentation. As Throwback suggests above, pull fuel pump relay 2 and see if you get an error code to work out which set of codes you should be using.

 

my car is a 2000 model

 

Also I did get a restricted performance message 2 times driving it around 50 miles

 

My 2000 XKR had the same, and left me with the same confusion. It was the right upper O2 sensor - not the fuel pump.
A real struggle to replace, very limited space and it sat like it was welded in place. Had to cut the cables, used a deep socket 22mm and several extensions along side the transmission underneath.
The hole in the bulkhead was not a solution on my car, it did not align with the sensor.

 

ok thanks a lot !!