Or you just replace the most likely worn out O2 sensor lol No sir All this is already been dealt with It is a bad catalytic converter that can't pass the flood test or whatever the test is called that the car runs on the converter and the computer gets reported back to that the cata...
2. Comparing the signals from the pre-cat air/fuel ratio (Front O2) sensor to the post-cat rear O2 sensor. 3. Checking the catalytic converter temperatures with the infrared thermometer. Temperature of the exhaust upstream from the catalytic converter. ...
So, to really simply things let's just say that the efficiency of the catalytic converter and/or exhaust pipe and/or O2 sensor is not so great. FYI this code is identical to P0430 however that code is for bank 2. You may even find you have both P0420 and P0430 trouble codes at ...
c. If the fault code returns during testing or the readiness monitors for the CAT do not pass (SYS.N.OK), then replace the CAT right away. 3. By forcing all of the readiness monitors, the oxygen (O2) sensor and secondary air injection (AIR) systems are being tested as well. If the...