O2 sensor alert to catalytic converter failure

[beatleknight]

Originally Posted by R3SP0NSE

Hey everyone,

I'm currently experiencing this check engine issue, has there been a fix figured out? I, for one, can't just ignore the light, it drives me nuts. I want it fixed and by reading the posts, it seems that a few people live with it, and others have tried O2 sensors.

What's the actual fix? I'd like to get a new cat if that's what it takes. But I want to know for sure. My latest error code was as follows

P0420 - CATALYST B1 EFFICIENCY BELOW THRESHOLD

Thanks in advance!

Lots of opinions but no definite answer. I too have the dreaded P0420 code at 71k miles. Guess I'll have to take it in to the dealer for a diagnostic. If its the cat itself then it should be free. Otherwise who knows which O2 sensor it could be and how much it could cost. We'll see.

[carolinaridgeline]

Originally Posted by beatleknight

Lots of opinions but no definite answer. I too have the dreaded P0420 code at 71k miles. Guess I'll have to take it in to the dealer for a diagnostic. If its the cat itself then it should be free. Otherwise who knows which O2 sensor it could be and how much it could cost. We'll see.

I get the same code at 155,600 miles on my 06. P0420 code, Bank one. I just hook up my ODBII scanner and erase code. Happens about every 1000 miles. Let us know what you find out Beatlenight.

[Silver 3.5]

A firend has an 06 Ridgeline and about 140K miles. He just got this code and I pulled it with my scan tool. Same P0420 code but...

1) Post cat O2 sensors are reading consistently flat lean condition indicating that the cats are doing their job.
2) Pre cat sensor on one of the banks looks a little lazy compared to the other one and to my Ridgeline.

Could this be an O2 sensor issue??

[Jackspt28]

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!

Jack George
Eastern Catalytic Technical Representative

[Jackspt28]

Honda Ridgeline (2006 model) Rear (firewall side) Catalytic converter image.

[xd9x19]

My Ridgeline started throwing the P0420 code a month or two ago. So far I've just reset it with my ODBII scanner each time. Usually shows up about once every tank of fuel.

[henni]

..just reset it with my ODBII scanner each time.

don't forget to rerun ILP since you have also lost the setting(s)

[John's Ridge]

I had the dealer replace my cat at 67k due to failure (under warranty). They blamed the high moisture content in gas due to ethanol. Made sense. Ethanol is bad news and I am too cheap to pay the extra 20-30 cents/gallon for all gas.

[diggitybiggity]

Hi everyone... just got a call from the dealer, the CAT is bad according to them. The truck has LESS than 80k miles on it, just purchased her used a couple months back. How do I know if this is covered under warranty or not? According to most posts in here you're saying if it has less than 80K miles it should be covered, but I see no where in the warranty information that this is the case. I have 100K mile power train warranty and a bumper to bumper 1 year or 7k mile warranty, but in the "Honda Care Warranty Manual" it states that this doesn't cover the CAT. If this is the case I'm going to be seriously annoyed, as I just drove off the lot with this thing less than 3 months ago and haven't even put 1K miles on it.

Any and ALL help/Opinions/Suggestion/Knowledge would be very welcome and helpful

thanks!!

[zroger73]

Originally Posted by diggitybiggity

Hi everyone... just got a call from the dealer, the CAT is bad according to them. The truck has LESS than 80k miles on it, just purchased her used a couple months back. How do I know if this is covered under warranty or not? According to most posts in here you're saying if it has less than 80K miles it should be covered, but I see no where in the warranty information that this is the case. I have 100K mile power train warranty and a bumper to bumper 1 year or 7k mile warranty, but in the "Honda Care Warranty Manual" it states that this doesn't cover the CAT. If this is the case I'm going to be seriously annoyed, as I just drove off the lot with this thing less than 3 months ago and haven't even put 1K miles on it.

Any and ALL help/Opinions/Suggestion/Knowledge would be very welcome and helpful

thanks!!

Per my 2010 Ridgeline Warranty manual, the catalytic converters are covered by Honda for 8 years or 80,000 miles under both the Federal and California emissions warranties.