Hello,

I have a 2001 Honda Accord EX 2dr 4cyl with a CEL warning. I had autozone read the warning and they told me that it is a 420 code. After a bit of research I decided to try replacing the O2 sensor near the catalytic converter under the car. It's has another near engine. In an attempt to remove the sensor I was unable to manually unscrew it due to rust, so I sprayed some liquid wrench to loosen to bolt. After letting it sit overnight I started the car and the CEL was gone. Unfortunately it reappeared after 30 mins. of driving. So my question is: Is this a clear indication that the CEL is caused by the O2 sensor and replacing it should remedy the problem.

note: I just remembered that I installed a new radio and removed the NEG battery terminal. Could this have anything to do with the CEL also?

Thanks,
Troy

 

P0420 - Deterioration of the Catalytic Converter.

Replacing the o2 sensor won't help. It's the cat.



Radio install has nothing to do with your error code.

 

The downstream o2 may set a DTC too if the catalytic converter is not doing it's job properly.

 

I was just informed by my mechanic that the "catalytic converter" in my Staten Island New York Dealer bought 2001 Honda Accord is California Compliant and that escalates the price to $1400 - is that possible?

 

Perhaps. Cats are very expensive. They're made with platinum. I would go to a muffler shop for it, though. The dealer will wring you dry.