I need help with code P0420 OBD II

Nikolov · Post by **Nikolov** » Fri Jul 04, 2008 9:52 pm

Hi, I have Daewoo Lanos SE 2000 , 1.6 engine. I got the P0420 OBD II trouble code. The guy at Oil Can Henry who read the code said that it is the O2 censor. I am wondering if I can continue driving with bad O2 censor or if I should replace it ASAP. I passed DEQ several months ago so I am good for almost two years. Any advise is appreciated.

Thank you.

daewoomofo · Post by **daewoomofo** » Fri Jul 04, 2008 9:56 pm

you can drive with a bad o2, but you run the risk of poor fuel mileage, leading to clogging the catalitic converter. you might also foul your spark plugs, causeing the engine to not run or run poorly. a new o2 isnt that expencive, trust me its worth changing

Pir0 · Post by **Pir0** » Fri Jul 04, 2008 9:57 pm

I personally would replace it as soon as you can. It could be causing your car to run rich, leaving a lot of carbon deposit in the chambers/on the spark plugs. Could be a matter of time before the plugs get that bad it'll start misfiring and be hard to start.

Not only that, but it'll cost you a bomb on fuel because it'll be running rich.

[EDIT]: Lol mofo got their first

Big Jeff · Post by **Big Jeff** » Fri Jul 04, 2008 9:58 pm

you should have it change. your engine could run Lean or rich which won't do any good to the engine

exist3nce · Post by **exist3nce** » Sat Jul 05, 2008 5:32 pm

Code P0420 is a catalyst efficiency code, not O2. Means your cat is either dead or dying.

Nikolov · Post by **Nikolov** » Sat Jul 05, 2008 6:16 pm

Thank you for the advice guys. I am paying very close attention on the gas millage. I have being getting around 23 miles per gallon for the last couple of years. I will try to fix it, the only thing is to find a trustworthy place to do it. I didn't have very good experience with the former daewoo dealer around here when I replaced my timing belt.

Pir0 · Post by **Pir0** » Sat Jul 05, 2008 6:48 pm

23mpg isnt all that good tbh lol.

A friend of mine has a gen6 [ i think ] 2.0 Celica GT which are notorious for being thirsty, and he complains about getting 24mpg.

Nikolov · Post by **Nikolov** » Sun Jul 06, 2008 12:53 am

Well I wish I could get more, but I drive in the city and using air conditioner, having trafic lights and traffic jams doesn't help too much. I am keeping the tires inflated and replacing the air filter often the only thing is I need to replace the fuel filter and keep my foot off the gas pedal. Otherwise on the highway I get around 28 miles per gallon.

MMamdouh · Post by **MMamdouh** » Sun Jul 06, 2008 10:39 am

exist3nce wrote:Code P0420 is a catalyst efficiency code, not O2. Means your cat is either dead or dying.

or a bad O2 sensor simulating a poor catalytic... you know the ECU checks for catalytic efficiency by comparing the reading of the first and second O2 sensors.

MMamdouh