P0420 Code On 2001 Corolla After Changing Maf And O2 Sensor - Toyota Corolla, Chevy Prizm (1998-2008)

kulkarni_ash

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

Ashish

http://www.obd-codes.com/trouble_codes/gen...hold-bank-1.php

google is your friend!

kulkarni_ash

I did check it, but wanted to find out if some had the same issue and was able to fix it

How much can i drive with this issue before changing the part,

and what is the cheapest way to do it

ashish

HiI did check it, but wanted to find out if some had the same issue and was able to fix it

How much can i drive with this issue before changing the part,
and what is the cheapest way to do it
ashish

This code is tripped by the after-cat O2 sensor. You might be able to back-probe that sensor for proper function. For this, you will have to remove the front passenger seat.

Proper values for the post-cat O2 sensor:

100-900 mV (no rapid fluctuations), median value 400 mV

heater resistance = 11-17 ohms

if these values are correct then you probably have a faulty cat. If not, change the post-cat O2 sensor.