Ok guys..... Ive searched and read just about every thread and still have no real answer and the check engine light is driving me crazy! .... I have a code 420... which i know is a problem with either a catalytic convertor... or either the A/F sensor, or o2 sensor.... the offical name for the code is "P0420 Catalyst System Efficiency Below Threshold (Bank 1)" (as found on https://www.yotatech.com/~corey/tech/dr_z_obd/dr_z.htm)
so i understand that the bank 1 states it is the first sensor or cat. so is the A/F sensor bad? or the first cat? I have 2 catalytic convertors so I gathered this is a CA emissions specific vehical... the last response i got to my problem was to take it to the dealer.... I have access to the same code reader the dealership uses and it would be the same thing... the above code... but i cannot find any other info on this. I just do not want to spend the money on repairing something that is not broken? the dealer down here is next to worthless and is terrible to deal with... the next closest one is about an hour away and I cant spare the 3 hours it would take this week...
ive also been reading how some people who have had problems with a dual cat system have just removed 1 of the catalytic convertors? i do not see how this would solve the problem... i would think there would still be a fault code there.... Im just trying to get this figured out cause that light is killing me.... please please please help me!

 

http://www.obd-codes.com/trouble_cod...old-bank-1.php

Theres your answer.

 

How many miles, and what vehicle are we talking about here?

 

Sorry i forgot to say in the first post... its a 1999 4runner with 132k.... so its past the 80,000 mile warrenty for the emissions... I read on the above post about the code and it makes more sense now... I will try that tommorrow and see how the power reads into the O2 sensor... any other info would be great.. thanks...

pat

 

If you do need to replace the sensor, be sure to get it from URD. www.urdusa.com. Best deal going.

 

instructions to change your 02 sensor by yours truly:

http://www.4runners.org/articles/02sensor

bob

 

You guys are the best... thanks

Pat