i got my cel light checked out and its p0420 which says catalyst efficiency below threshold... so to a simpleton like me wut does that mean? is it my o2 sensor by the cat or is it the cat itself? i switched to a magnaflow hi flow cat in the summer of 06 so wut do u guys think?
People say it's the cat or the sensor... basically the downstream o2 isn't reading right. I've had that code since I bought the car in 05... dunno how to fix it yet.
Corsica Dude wrote:People say it's the cat or the sensor... basically the downstream o2 isn't reading right. I've had that code since I bought the car in 05... dunno how to fix it yet.
lol wow... have u done anything to get rid of it? the first thing i did was change the cat and clear it... so i guess i should try changin the sensor now and then clearing it..
i haven't done anything as far as replacing it yet... i tried clearing the code, and usually it'll stay off for about 2 weeks, then it comes back. It might be the sensor, they're pricey as hell though
The sensor is cheaper than the cat, or should be. Hey Corsica, if your car has less than 80k miles, your cat is still under warranty, see if you can have the dealer test it and if needed replace it under warranty. The O2 sensors I believe are under a 5yr 50k miles warranty though.
they arent that expansive unless you get one from the dealer.
I had the same cat and had to replace the 02 about a year later. the sensor fails sooner w/ a high flow cat. the cat will also fail sooner. im on my second one.
