I'm really at a loss on what to do about this code. I'm hoping somebody on TW can help me out. I've got a 02 PreRunner with about 160K miles. As far as I know, the catalytic convertor, O2 Sensor and A/F Sensor have not been changed.
I recently got the P0420 code. I read up on the forums and did some of the inspection checks listed in the FSM - DTC P0420. I checked for exhaust leaks, but didn't notice any. I used my voltmeter and both sensors seem to be in tolerance. I removed the A/F sensor and cleaned it in SeaFoam then sucked about a 1/4 cup of SeaFoam into my PCV Valve to clean out any engine carbon build-up. I got Advance Auto Parts to clear the code and thought everything was cool.
Then a couple of weeks later, the code hit again on my way to work. I'm at a loss what to do. Here's my thoughts... 1. Clean the O2 sensor (I haven't done this yet since I didn't have a deep 12mm socket to reach over the heat shield.) 2. Pickup a OBDII Checker and do my own "OBD II ACTIVE TEST". (This may give me an excuse to buy a BlueTooth OBDII.) 3. Replace catalytic converter. (Not too excited about this one. RockAuto lists a WALKER Cat# 53432 for $170, but I'm thinking installation will probably be costly.)
Has anybody successfully solved this problem?