Hello all, I'm new here and have actually never been to a car forum before but curious if someone can possibly explain or help answer some questions for me. I have a 99 Honda Accord, 4 cylinder 2.3 L vtech engine that has about 170K miles. The check engine light comes on/off sometimes and I recently went to an Autozone as I was running errands and my car was kinda like puttering at the stop light. Now I've had it ran through the "machine" a few times when the light has come on, and I've got the code that is for the O2 sensor. Today when I stopped by Autozone and they ran it, they got the codes P1361 & P0420. Basically dude there told me that it could be that I need a tune up (which I do here soon anyways) or could be that some of the spark plugs need to be replaced.

Now normally I would ask my mechanic, but sometimes, it's nice to hear what others have experienced or what type of action that I could/should take. I also am curious to where are some good sites to look for a catalytic converter that will be good quality, but won't cost me an arm and a leg!!!

The codes on that machine said:
P1361-Manufacturer Control Ignition System or Misfire
P0420-Catalyst Efficiency Below Threshold

 

P0420 is basically either you need the O2 sensor for the before and after the catalytic converter. my son's 04 malibu has the same issue. i'd replace the "before" sensor and i monitored his MPG on every fill up to see the difference on his mileage. its good but i still get the same codes come out but i just clear it with my code reader. his mileage is still good so i think that the computer on my son's car will eventually reset itself. the other code P1361,as you said and that dude mentioned a tune up might be needed and check your spark plugs for wear and gaps. replace if necessary. heck! repalce them anyways,get the NGK iridium plugs,they work really good.also what i've done to my car is have my injectors cleaned,that really help out on my issue with bogging down while city driving. the only place i can think of that has reasonable priced CC is on ebay. but check around your area for any good sale on those or ask some friends or relatives, like networking for CC. goodluck

 

P0420 can be caused by O2 sensor, but the meaning of this code is the catalytic converter efficiency (determined by O2 sensor aft of converter) is below expected performance. The rear O2 sensor performance is monitored by the ECU and when a certain signal (high number of voltage spikes/troughs of output voltage) is detected code P0420 is set. This condition can be caused by exhaust leaks ahead of converter (air is pulled into exhaust), possibly slow O2 sensor ahead of converter, or failed catalytic converter matrix.

I had this failure on a different brand (Subaru), and monitored w/ an OBD2 scanner to confirm before replacing the converter.

There are some "direct fit" replacement converters, other than OEM which are $$$$. Eastern catalytic is one I purchased but there are others (names escape me at the moment). I was not totally happy w/ quality of my Eastern Catalytic converter. It fit but barely and had an extra O2 sensor bung that my car did not need and no way to plug. I had to rig a plug.

I would suggest getting some professional help to assess what is happening, but unless you find some exhaust leaks, the most likely explanation is failed catalytic converter.

BTW, trukid21, the reason the code returns is the same rear O2 sensor performance is being detected indicating failed converter or possible exhaust system leak.

good luck

 

BTW, trukid21, the reason the code returns is the same rear O2 sensor performance is being detected indicating failed converter or possible exhaust system leak.

just hoping man,LOL! but i think my son 's catalytic converter needs replacing. its an 04 malibu with 88000+ in them i read about it and its one of the things that was quite needed replacing on that type of car with that amount of mileage. also my son car showed a O2 sensor malfuction(upper bank)first, then the P0420 codes soon afterward when i cleared the first code.

 

Especially for codes above P0999, you have to be careful about the text that shows up on the code readers. Anything above P0999 can mean completely different things for different car companies.

For Honda, P1361 actually means "TDC Sensor Intermittent failure".
On your 99, that sensor is down by the crankshaft pulley; in fact you have to remove the timing belt to replace it.

Intermittent problem with the TDC sensor can cause misfiring, which in turn might have caused the P0420...

 

Okay well this post was made Friday when I got home. I woke up Saturday and it puttered out/died three times in my driveway. Had to work all weekend and haven't been back online. My mechanic is a personal friend that usually just fixes whatever the problem is and sometimes doesn't really explain what's going on which is kinda peaking my interest lately with this code (the catalytic converter one). I got this car in 2001 use and can't remember to this day if I have ever had a tune up on it (since my mechanic usually does it and he doesn't remember either). So needless to say all that, he came and got it today. Had his son drive it to his shop and his son said he had problems getting it over 40 mph but it never puttered on him or died apparently cause he never said that to me. I went and got it after working and school today. He did a tune up since the plugs were totally bad he said. It drives fine now and I got it up to 70 mph with no problems. I still think that replacing the catalytic converter might not be a bad idea either but maybe ya'll can give me a little advise on that part. My mechanic didn't say that I needed to replace it, but also mentioned that replacing the timing belt might be a good idea too.

So I suppose after any other advise that ya'll could give, is what exactly is included in a tune up?

I know ya'll might think that I'm some dumb airhead or something, but that's not the case. Just never really had to deal with anything regarding fixing my car. Although as I'm getting older, thought it may be a good idea to know some stuff like this. Thanks in advance for any info and also thank you all for posting so far.

 

If the check engine light does not return, then I would not replace the catalytic converter. It is an expensive part. The tune-up might have corrected the problem.

The tune-up likely consisted of changing the spark plugs, distributor cap, distributor rotor, and air filter. It should help your car get a better spark to each cylinder.

As for your question about the timing belt, there are to be changed at specific intervals (every 90K miles on my 95). Your 99 may be different. That information should be in the owner's manual under the maintenance schedule. If not, then someone on this forum should be able to tell you when it is due.

If you timing belt is due, get that changed. If the belt breaks, then you are in for a huge repair bill, because the engine will likely get damaged.

 

On my 98 Accord 4-cyl, the timing belt interval was 105k miles. Not too much different than 90k...

 

Lol, okay well it's overdue then. I bought it with 37K miles and it's got over 140K now.

I've still yet to get the bill for the tune up so when I get that I suppose I'll schedule the timing belt as well.

Thanks all for your help