The last time I had upstream O2 sensor problems, the engine management light stayed on until they were changed for new ones, then all as well.
My recent purchase shows a P1647 code but I don't get the check engine light coming on.
This model's dash lights are different to my 2002 model 4.0 Sovereign, as the 2002 has a engine shaped RED light. Whereas the 1999 has the words CHECK ENGINE in Orange, which goes out when the engine is started.
I still have the P1647 sensor code, but no lights on the 1999 XJ8.

Do I have a problem with the sensor? If so, can I prove it first without replacing the sensor????

Thanks Bill W

 

Can anyone help me on this one ??? Thanks Bill W.

 

Does the code keep coming back? fuel trims - how do they look, a bunch of info on here to show how you interpret long term and short term fuel trims, your code reader should give you that info.

 

Thanks Sean, I will look on the site for the fuel trim info. Yes, they come back when cleared. Bill W