Code P0420 and "lazy" O2 Sensor on 98 Corolla - Toyota Nation Forum : Toyota Car and Truck Forums

petec · 09-20-2005, 05:04 PM

I recently posted a problem with my new (to me) 1998 Corolla.

www.toyotanation.com/forum/t95701.html

So I cleared the code (P0420) and it usually took 20 miles or so before the code showed up again. I did this several times.

Why does the code take so long to reappear?

Somewhere else I recall seeing a post about a "lazy" O2 sensor. Is it possible the problem is with the O2 sensor and not the catalytic converter?

fredk · 09-20-2005, 09:27 PM

how many miles and whitch sensor?

petec · 09-21-2005, 10:15 AM

161,000 highway miles.

Isn't the P0420 code a result of out-of-spec difference in readings between the before the cat converter and after the cat converter O2 sensors? So I don't know how you determine which sensor is reading out of spec.

BTW the car runs great and is getting good gas mileage so far.

Can I damage anything by continuing to run the car in this conditions?

deekay140 · 09-21-2005, 10:58 AM

Like I Said Before, U Need A New Cat

petec · 09-21-2005, 11:11 AM

Bummer.

Where is the best place to get one cheap? I will put it in.

fredk · 09-21-2005, 05:18 PM

kitty time