ROC Rank: Freshman
Join Date: Dec 2012
Model: *Former Ridgeline Owner
Model Year: 2006
Color: White / Olive
Re: O2 sensor alert to catalytic converter failure
Hello, Sorry to hear you are having issues. The P0420 code refers to bank 1 Catalyst which on Honda is The firewall side of the engine. P0430 refers to the Radiator side catalyst.
OEM Catalytic converters should last at least 150,000 miles as long as they have been treated properly. By treated properly I mean that the vehicle has been maintained properly and never had any issues such as a misfire, or any other issues that affect proper air/fuel ratios.
A misfiring engine can ruin a catalytic converter in short time. The excessive emissions (unburned or partially burned fuel) entering the converter can cause the converter to overheat and ruin the precious metal coating in the converter honeycomb (substrate material). Once this happens the converter will become inefficient at proceessing the exhauat gasses.
Any vehicle problem that affects the air /fuel mixture such as MAF sensor issues, 02 sensor faults ,fuel injector problems like dirty injectors, excessive carbon build up on the intake valves and combustion chambers, faulty or lazy O2 sensors, coil problems, and base engine issues such as worn engine components, and oil consumption issues can ruin the converters.
The codes P0420 (bank 1) and P0430 (bank 2) ,simply means that the converters have been deemed inefficient by the vehicles onboard diagnostic monitors.This doesn't necessarily mean the converters are are bad or clogged (although they could be clogged, which would result in a drastic reduction in power and fuel economy and usually will set other fault codes along with the converter codes.).
Very often the upstream O2 sensor is defective, or lazy (slow switching rate). When this happens the computors onboard catalyst monitor precieves the catalyst is inefficient because of the false readings reported by the lazy upstrem O2 sensor. In reality the vehicle may only need an O2 senor for the affected bank of cylinders.The catalyst may be OK.
The Key is in the diagnostics. Simply getting the code read at your local Autozone is not considered proper diagnostics. It simply gives you the area to start the diagnostic routine.
If you have experienced running issues such as a misfire, a faulty sensor like a MAF sensor, O2 sensor, coolant temperature sensor, or intake vacuum leaks etc.in the past 6 months ,the converters may have been damaged and eventually triggered the P0420/P0430 Catalyst efficiency codes.
Have the vehicle diagnosed properly by a trained professional to be sure the converter(s) are the only problem and not the result of another underlying vehicle problem.Testing should include overall engine condition, Fuel trim analysis, converter temperature tests, and O2 sensor evaluation.
Failure to properly repair the root cause of the issue can result in another expensive catalytic converter failure.
I always recommend replacing the O2 sensors on vehicles with more than 80,000 miles,when replacing the catalytic converter (s). Most manufactures recommend O2 sensor replacement at 100K. I also recommend fuel Injector cleaning, and induction system cleaning (motorvac/seaFoam,Etc.) on vehicles with more than 100,000 miles prior to replacing the converter(s).
Good Luck and Happy New Year!
Eastern Catalytic Technical Representative