I purchased a scanner today and it came up reading 2 errors:

catalyst efficiency below normal (bank 1) P0420
catalyst efficiency below normal (bank 2) P0430

I have tried googling the characteristics and symptoms of the situation, but I was just posting to see ideas on how to approach this problem first.

2005 V6 Honda Accord Coupe
138,xxx miles

I have been driving the car for awhile, the Check Engine Light turns on/off every so often. It would turn on for a week then off for a couple of days, and then back again. Kind of weird.

Thanks in advance.

 

Please post the actual trouble codes.

 

My mistake, it is up now.

 

How many miles are on the car?

 

138,xxx

 

Federal emission warranty which covers the cats for 8 year/80,000 miles would be over then.

Your car has 3 converters, the codes relate to the ones shown in the attached pic.

A little unusual if both cats were bad though. I'll see if I can find anything more.

 

For now, use the code reader/scanner to clear the stored codes. See if they come back after you driven awhile. It may take awhile before the code(s) come back or they may not even come back.

 

I have been driving the car for awhile, the Check Engine Light turns on/off every so often. It was on about 3 weeks ago then turned off a week following that, and it returned again today.

 

I couldn't really find anything more for your 2005 V6.

This Honda TSB was related to the 4 cylinders (which is not the same as your): Honda TSB 03-063

 

Do you have any clue on why my CEL goes on and off every few days/weeks? It will turn off then on then back to off every so often.