Error Code P1646 Heated Oxygen Sensor Bank 1, 2002.5 4.2 NA S Type

After getting 9.5L/100km on a trip I’m getting rough idle and poor mileage.
DTC P1646 now showing,
Wondering if anyone has the part numbers for the sensors?
Brands to use, e.g. NGK ?
Mine is a high mileage vehicle and I read that the sensors should be replaced periodically?
Any advice will be appreciated.

So… I took the sensors out and swapped them over. Error code now reads Bank 2. I guess that “proves” that the Bank 1 sensor was faulty. The sensors are marked Denso 192400-3101 03B07
I understand that the same part also has designation DOX0430.
I’ve found some sensors at a cheaper price e.g. NTK 02A687-D2 which are supposed to “fits your vehicle” but connector looks different in online pictures…I’m thinking of using my connectors and soldering to the new ones ???
Thanks for reading and any advice. Has anyone else experienced problems with their Heated Oxygen Sensors?

Wow… I’ve been quoted up to Aud $600.00 for a new replacement sensor. Thanks to a local Jaguar business I bought a used replacement for $95.00. Error code gone!

This “Pre Cat” sensor was easy to get to but only on ramps there was not much room for leverage.
It’s a 7/8" /22mm and all I had was a shifter. This worked with only slight rounding of the hex.
Then I discovered there is a tool for the job…surprise, surprise. A $19.00 investment and now I have another tool that looks good in my tool chest but may sit there for a long time between uses.

I’m still interested in views on periodic replacement of these sensors… Any thoughts?

As far as I know o2 sensors are not routine replacement items. I had an X308 XJR for 17 years and never needed to replace them, and I’m not planning to replace the ones on my current S-type R unless there’s a problem.

Nothing lasts forever, but I wouldn’t consider these devices a routine replacement item. They usually go bad when some other problem takes them out (exposure to leaded fuel, sudden exposure to moisture, or super-rich/lean fuel mixtures.)

If nothing else, at least in the USA, as a crucial emissions component they have to be certified to last for a very long time (100,000 miles at least? Maybe more.)


Thanks Dave, much appreciated. :