CEL on...code p0420. had autozone reset it.

the guy said (off the record and not as an autozone employee): "disconnect the exhaust system and run a stick or broom handle up into the cat conv to open it up".

hmmmm....sounds like a bad idea to me. anybody else want to weigh in?

 

I'd have to say "WTF?!?" Why on earth would anyone give such stupid advice. If the cat converter was actually below effieciency before what do you think it's going to be with the catalyst removed? If the cat was actually bad then the cheapest way to handle it is to remove the lower O2 sensor and zip tie it somewhere out of the way. (It always reads fresh air then) Screw a plug or an old O2 sensor in the open hole. It's a heated sensor so don't put it anywhere close to plastic parts.

In my case it was the lower O2 sensor needing replacement. How many miles does yours have on it? More than 100k? Replace it. Mine had 175k before it died.

 

thanks. but which O2 sensor to replace? there's 2 of them. is it the one on the top (easy to get to) or the one waaaaaaaaay down there (not so easy to get to)?

thanks again!

 

The lower one. Called the Downstream sensor. This is the one that tells you whether the cat converter is performing correctly as it's located after the cat. It's easy to access from under the car.

Buy Bosch Premium Oxygen Sensor 16292 at Advance Auto Parts

 

awesome....thanks for the link also!