Greetings all. Posting on behalf of my GFs 2000 Impreza wagon with around 125K miles on it.
Check engine light came on and Autozone says it's P0420 - Catalytic Converter Efficiency Below Threshold on bank one.
It comes on every few weeks and I just disconnect the battery/beep horn/reconnect battery to clear. Every third or fourth time it comes back my girlfriend forces me to go BACK to Autozone to ensure it's the same code (which it always is).
Unmodded, and stock exhaust as far as I can tell.
Trying to explain to my girlfriend that this code is not dangerous to her or that the car is not two miles away from exploding has been a challenge, to say the least.
I thought it was cat related till the most recent autozone guy said, "No, it's your front O2 sensor..see it says 'bank one'" but then I came here and I'm again convinced it's cat related.
Either way, I'd like the code to go away. Car will be driven for another year, two at most, and I'm pretty sure it will pass PA inspection, but only vanquishing the code will provide me with respite from my girlfriend.
Not above gettting my hands dirty and will fix the problem if it's under $150 or so, but if the fix is more expensive than that, then disabling the code is more my concern.
So, all that being said, here are my questions.
1) Front O2, cat, Rear O2..what's the most likely cuprit?
2) How does one go about disabling this CEL?
Thanks in advance!