Question Code P0420 ? - Toyota Tundra Forums : Tundra Solutions Forum

mcarthurp · #1 (**permalink**) 10-26-2008, 09:48 PM

My silly engine light is on and after a trip to Autozone I got a troubleshooting code P0420 which stated: The PCM has determined the the catalyst system efficiency for BANK 1 is below threshold for the current engine operating conditions. I think that means that one of my oxygen sensors are bad. Does anybody know which Oxygen sensor is matched to Bank 1? Could this be some other problem than an oxygen sensor? Does anybody have and ideas or suggestions? My car is a 2000 with 127K miles with good regular maintenance. If the oxygen sensor is out does it really make any difference in the way the car runs or it's longevity?

Pat

mcarthurp · #2 (**permalink**) 10-28-2008, 05:16 PM

I took the negative terminal off the battery for about 15 minutes to reset the computer and when I started the car the check engine light had disappeared.

Pat

Kaptaink · #3 (**permalink**) 12-08-2008, 08:35 PM

I believe there are two O2 sensors on bank 1 .... sensor 1 and 2. My Auto Zone guy was pretty sharp and somehow iliminated sensor 1. I dont think either one is cheap... Auto Zone had a Borsch brand for $199 but I believe the Toyota brand is nearer to $100.
Removing the neg battery cable will reset the check engine light but if the problem still exists it will come back on after the several cycles.