2002 Toyota Corolla CEL / Catalytic Converter

LANELANE

MEMBER
2002 TOYOTA COROLLA
4 CYL
FWD
AUTOMATIC
249,000 MILES

Check engine light has been on for a year. Last year at this time the light was on and I had to get it inspected. Ended up having a new converter put on. Light went off and it passed inspection. However light came on about two months later and has been on ever since. Well. It's time for inspection again lol.

Code: P0420
catalyst system efficiency below threshold-bank 1
Probable cause:
air leak in exhaust before rear h02S
af sensor error
fuel system fault
faulty catalytic converter

I have had the oyygen sensor (bank1) replaced. Drove car for 30 miles and light came back on. My question is: what should I do next? Replace other sensor or catalytic converter? Or both?
I took it to Meineke. They said I needed a California Converter for my car and they said the total for part and labor would be $600. Does anybody have any thoughts or suggestions on what I should do. Thanks in advance!

3 Replies

MHPAUTOS

MECHANIC
31,937 POSTS

Hi there,

I would be looking for an up stream of the )2 sensor exhaust leak, also a vacuum leak, you can get the air flow sensor tested, unfortunately as I am in Australia, I am unaware of any different converters required for Cal, I will check this out and post back any info.

Mark (mhpautos)