P0420 Code On 2001 Corolla After Changing Maf And O2 Sensor

[kulkarni_ash]

Hi
I have a 2001 Toyota corolla has 126,000 miles on it.
I recently changed MAF and O2 Sensor because of P0171 code, i drow about 1500 miles after that and now i get check engine light again, this time it is P0420,
I took it to Autozone and the guy said it is because of hot and humid weather, and so i cleared it with his machine.
But after drivint about 500 miles the code back on, and it was again a very hot and humid day
How do i fix this issue,
does it mean i have to eat bullet and change catalyst converter?

Please help

[digger89]

Try a can of fuel-injection cleaner and reset the code, worked for me for about 300 miles so far! Cheaper than a new CC.

If your car is getting good MPG, good acceleration, etc., then the P0420 code won't hurt your engine, it will hurt the tailpipe if you need to pass emissions.

[2001CorollaS]

Seafoam treatment and throttle body cleaning got rid of mine.

[bonnie*]

read the following thread, updated continously
check engine light
http://www.toyotanation.com/forum/sh...05#post1573505

[medicstudent01]

How much oil does it burn?

[vvvvv]

My 04 corolla's checking light was on, had it check in one shop, and was told that the o2 sensors were bad. Bought 2 Borsh o2 sensors from advanced auto parts and replaced them. But the light was still on. Went to an AAA shop. They told me that the front o2 sensor was still bad, since the car has to meet CA emission requirement and needs special front o2 sensor. The guy in the shop has 20+ years with Toyota and called Toyota dealer. He provided them with the VIN, and dealer told him that. Ordered the part from dealer, but have to wait for few days.

[ToyotaHeart]

View the traces on the rear O2 versus the front O2. It's probably the cat with the damage from the oil.