it's a oxygen sensor heater fault.. for a upstreamoxygen sensor bank 1 (which is passenger side.)

 

I also have code 1647.
I switched the o2 connectors and I get the code 1646.
I know these are upstream.
My question is: which is 1647? is it the upper or lower sensor?
99 Jag VDP.
Just replaced battery, fuel pump, fuel filter also spent days trying to trace a short which tuned out to be the fuel inertia switch.
Hopefully this o2 sensor is it!
I am at wits end!

 

You can do a search on this and get more info.

This is for the left side front/upper sensor. The heater has failed.

On mine I had to remove the coolant recovery tank and the heat shield to get to the sensor -- you will absolutely need a some type of sensor wrench to get to it from above. I ordered the correct Bosch sensor from Amazon as well as two different sensor wrenches to do the job - The one with the handle attached was needed for my skill level - you may have another way of doing it. Also, you can suck out the coolant from the tank and remove it without any additional coolant coming out of the lower connection hose -- I still blocked the hose off with tape -- then I just reused the same coolant after I put the tank back in.

The original sensor that I removed was a four wire Denso - the Bosch was a direct replacement.

You need to do a little investigation as Jag changed the type of sensor -- around 2000 I believe -- but you want to get the correct one. Also get a direct fit and not one of the universal units that you have to attach the plug - people have had running problems.

Its not a difficult job -- just a little frustrating at times moving the heat shield out of the way and trying to remove the sensor. The heat shield does not come out you have to move it out of the way and my sensor needed some WD40 and an hour to come free.