Catalytic Converter and or O2 sensors?

[TAckhouse1]

Hey all, my 2004 LX 470 (228k miles) has on two occasions shown a check engine light along with the VSC Trac/VSC off. In both cases, it turned off on it's own after about a 3-5 days. My mechanic checked the codes and said that the bank two catalytic converter is showing an error message. After reading through the threads on this board, I understand that more often than not it's a bad O2 sensor that causes this sort of error, not a bad catalytic converter. With that in mind I ask my mechanic to check the O2 sensors, he responded that none of them are showing any errors codes. He is willing to replace all 4 of them for me (for $850), but he still thinks the issue is with the cat itself. I believe he said it would be in the range of $2000 to replace both cats with OEM units.

Any thoughts from the group? Should I replace the O2 sensors first? Or maybe just the two lower O2's sensors (as I understand they are easier to access)? I obviously don't want to waste money unnecessarily, but unfortunately Nevada has emissions testing, so I need to get the resolved before January.

Many thanks in advance.

Nick

 

[JunkCrzr89]

What are the codes?

 

[TAckhouse1]

What are the codes?

I'll get that info and report back

 

[TAckhouse1]

Here are the codes ^

 

[Mars06LC]

0455 could be gas cap or vacuum line somewhere (though I'd do a search on here). P0430 (and it's twin 0420) are pretty common, there are a few big threads on them - looks like you read them. I had 0420 and 30 and put O2 sensor spacers on and it works - still passes emissions (but I don't think VA does a sniffer test, just checks for CELs). Beyond that start small and work your way up. Don't throw cats at it unless it's the last resort. Good luck

 

[BullElk]

I had 0420 and 30 and put O2 sensor spacers on and it works

Notice anything different with the spacers?

 

[TAckhouse1]

0455 could be gas cap or vacuum line somewhere (though I'd do a search on here). P0430 (and it's twin 0420) are pretty common, there are a few big threads on them - looks like you read them. I had 0420 and 30 and put O2 sensor spacers on and it works - still passes emissions (but I don't think VA does a sniffer test, just checks for CELs). Beyond that start small and work your way up. Don't throw cats at it unless it's the last resort. Good luck

Do you think the codes are related? (as in the evap leak could cause the Cat to read off?)

Researching, it seems like replacing the gas cap is a easy fix to try. Another one is the evap canister vent valve.

Nevada doesn't do a sniffer test, just checks for CEL's. That said, I plan to own this truck for a long time, I'd like to get it fixed right.

 

[Mars06LC]

Notice anything different with the spacers?

Exhaust usually smells a bit gassy. Not sure if that's due to a bad O2 reading leading to rich condition or what. But nothing besides.

 

[Mars06LC]

Do you think the codes are related? (as in the evap leak could cause the Cat to read off?)

Researching, it seems like replacing the gas cap is a easy fix to try. Another one is the evap canister vent valve.

Nevada doesn't do a sniffer test, just checks for CEL's. That said, I plan to own this truck for a long time, I'd like to get it fixed right.

I don't think they'd be related. We do have a whole host of charcoal canister/evap stuff on our cars though I've never had issues with mine. Also look around for vacuum leaks. Not too well versed on it.