Hello all, New to this forum as well as new to the Jaguar ownership. Love my Jag but have failed my Emissions test for al three test and would like some advice on how to fix it. I belive it because of the levels I failed at I may have bad O2 sensors or bad Cats. I would like an help from anyone one who has had this issue with a similar vehicle.

the V12 is a beast and I love it and cant wait to get it registered to start driving it daily.

 

Please post your results from the test.
How many miles on the car?
Is your check engine light lit?
Any codes displaying on the trip computer?
Does your air pump cycle on and off?
Help us out...

If the O2 sensors were bad you would get a fault code.

If there are no fault codes, and regular tune up stuff didn't help (spark plugs, wires, clean the inside of the distributer cap and the rotor, etc.) then I would start to think that one or more of your cats are bad/damaged.

The air injection tubes get clogged up after many years, but if they were really bad, you would get a fault code as the ECU would not see the change in readings from the O2 sensors.

If one of the coils died in the past, or it had a Marrelli rotor failure in the past, then almost certainly the cats on that side will have been compromised.