Volvo S80 catalytic converters code

SOURCE: engine light keeps coming on, had catalytic converter replaced 2x

a bad or disconnected oxygen sensor will make the engine run rich.
How about a clogged air filter? 

SOURCE: volvo 2002 S80 T6 - codes P0011 and P0011

Weell it sounds like you have the days old problem Pepole dont know how to look after there cars.
The muck you still have in the engine isent doing it any good and so you have to get rid of it all, as its in the engine block and is got to go ,,so drain a little of water out and put in 1/2 a cup of washing up liquid in the radiator and start the engine and let it get hot and take the reves up to 1000 rpm now and then to keep the water going around the system, after about 1/4 hr turn off,,stand for 10 minutes ,,and then remove the cap slowly and then take off the Bottom hose and let all water out also take off Top hose at the engine end and put the house water hose in the top and turn it on till all water comes out clean. Then put hose up into the bottom hose and do the same again ,and the same in top again.Now with a clean engine you can do the same to the new Radiator and wash out all gunk .then check the thermostat and make sure its 100% (any doubt through it out) and take note how it comes out so you can fit a new one the same way,
Now refit both hoses and fill with coolant or antifreeze and TURN on the heater to hot before starting as you also have to get out the air from heater when it was drained and you will trap the air which might cause you code problems..
But now try service light reset
1,,Turn Ignition to Number 1position.
2,,Press and hold "day counter"reset button and turn
ignition to II(second) position,hold down for about 12 seconds.
3,,Afterservice light flashes,release button,there should be 2 beeps confirming reset was successful.
Let me know how you get on .. Ron

SOURCE: catalytic converter or oxygen sensors?

i would replace the oxygen sensor first as it is the cheapest and easiest

SOURCE: catalytic converter check engine light 2001 s60 volvo

usually if you start to hear a rumble, and by rumble i mean it sounds like a bunch of pieces of metal are clanking around in your exhaust then the catalytic converter needs to be repaired. It could also be the oxygen sensor which is located on top of the converter. Volvo did an interesting job of having them sit on top of each other.

Testimonial: "thank you for your answer, it has been very helpful"

SOURCE: I have a 2003 Volvo S60T. The check engine light

go to volvo of america.com