My '03 recently triggered this code P0420 "Catalyst System Efficiency Below Threshold (Bank 1)".
When I searched this forum someone mentioned something about the engine consuming oil. Which could trigger this code. Not sure if this the case in my Jeep but I've noticed that after several thousand kilometers the engine oil level gets very low. Yesterday I added three Liters of oil after using the car for about 4000 kilometers. I am using 5W-40 synthetic engine oil. I don't have any leaks in the engine and there is no smoke suggesting a bad piston ring or so. Shouldn't there be a light in the dash for low oil level?
Should I deal with this as one? Or two different issues?
Note that the engine oil thing was happening for about a year now. Never had the time to look into it. I've always checked the oil level and just keep adding oil till the next change.