I HAVE A 1998 ACCORD, 6 CYLINDER, 120,000 KM. ENGINE ATTENTION LIGHT CAME ON (THE ONE THAT LIGHTS UP WHEN A COMPUTER CODE SHOWS UP). WAS TOLD THAT I NEEDED A NEW CAT. GOT ONE. LIGHT STILL COMES ON. I AM NOW TOLD THAT I NEED AN OXYGEN SENSOR (OR PERHAPS TWO). AM TOLD THAT IT IS NOT UNCOMMON FOR THE OXYGEN SENSOR TO BE DAMAGED WHEN A CAT GOES.

I HAVE ALWAYS SUSPECTED THAT I NEVER REALLY NEEDED A NEW CAT. I COULDN'T IMAGINE THAT A CAT WOULD GO WITH ONLY 115,000 KM.

DOES ANY ONE KNOW THE CODE THAT CALLS FOR A NEW CAT? I THINK IT MIGHT BE P0420. IS THERE A SEPARATE CODE TO SHOW THAT THE OXYGEN SENSOR IS KAPUTT? ARE THERE TWO SEPARATE OXYGEN SENSOR CODES, SINCE THERE ARE TWO SEPARATE SENSORS?

THE REASON I WANT TO KNOW THESE CODES IS THAT AFTER THE CAT WAS REPLACED, AND THE LIGHT CAME BACK ON THE CODE THAT SHOWED UP WAS P0420. THEY CLEARED THAT CODE, AND I WAS TOLD THAT IF THE LIGHT REAPPEARS, I WILL NEED A NEW SENSOR. IF P0420 IS IN FACT THE CAT CODE, WHY IS IT COMING ON WHEN THE CAT IS NEW? IF P0420 IS IN FACT THE CAT CODE, WHY WOULD ONE REPLACE THE SENSOR?

ALL HELP AND IDEAS WOULD BE APPRECIATED.

 

First lose the ALL CAPS. It's harder to read and considered rude.

P0420 is code for inadequate catalytic converter performance. It's likely the pre-existing problem that caused this code was not resolved. It can be a bad catalytic converter, but could also be leaking exhaust manifold, poorly connected catalytic converter, bad primary O2 sensor, or less likely bad secondary O2 sensor. A good shop should have checked all these other (less expensive possibilities) before selling you a new converter. If they didn't I would find a new shop.

good luck