After swapping a 97 engine into a 95 xjr i have drive it for a few days and the cel has come on. The codes are P0420, P0430, and P1199. I think the p1199 is because my fuel gage isn't working. Is there any sensors or grounds i need to check to get this working? The po said he put some fuel cleaner in the tank and the gage worked.. Idk if I believe it. The other two I'm not as sure about. Will it hurt the car if it's driven 20miles a day with these codes? It also has the trac fail light on. I'm assuming this is the traction controll..
-Dayn

 

After a bit of research Im thinking the other two codes are something to do with the 02 sensors. I know that my rear exhaust manifold has a hairline crack in it so this may be causing the problem. I saw it when I replaced the engine and was hoping it wasn't all the way through yet.. Would that cause both those codes or do I need to keep looking? Thanks.
-Dayn

 

Are the o2 sensors that are throwing this code the ones located on the down pipe, or are they further down the exhaust system?
i think im going to try to repair the extra cracked rear exhaust manifold and re install it. im going to tap and plug the hole for the egr that my car doesnt have ( this manifold is off a 97 mines a 95) and im going to drill two small holes at the ends of the crack and bevel and weld up the crack and holes. im a welder as a profesion, i just dont work with cast often so hopefully it will hold up fine. im hoping this will correct the codes my car has. any input?

 

Anybody have any input?
Dayn.

 

P0420 and P0430 have been the bane of my existance...and other X300 owners as well. I've had an on again/off again battle with them for several years.

Both codes refer to real or "perceived" cat converter inefficiency. Faulty cat converters, faulty oxygen sensors, or air leaks (intake or exhaust) can trigger the codes.

In my case the 430 and 420 codes are always accompanied by a LTFT (Long Term Fuel trim) reading that spikes to "100"...which is an anomoly. Other X300 owners have reported abnormally high LTFT readings as well.

At least one of us cured the problem with a new TPS (throttle position sensor) and a re-orientation of the system (which requires specific equipment to accomplish).

A scan tool that provides a live data stream will show if your oxy sensors are working. Any air leaks will have to be found and sorted out. That's about as much as a DIYer without re-orientation equipment can do.

Hopefully others will chime in. I haven't had the codes for some time but I'm sure they'll pop up again. I just clear the codes and carry on. The cars runs great and gets great mileage. If you live in an area with emissions testing, though, it might be a problem.

Sorry I don't have a good answer for you

Cheers
DD

 

That does help thank you. I have cleard
Them and they came back. I'm going to repair the extra exhaust manifold I have and install that clear the codes and see if they come back again. Ive noticed when I'm driving and cruising at a constant speed the car lurches a bit and the rpms change a bit. I'm trying to sort out if it's an engine or tranny issue..
Dayn.