Rep Power: 0

I AM MURPHY'S LAW!!!

I just bought this car last week. It has 37000 miles and does not have a warranty. 3 Days ago the Malf. Indicator came on. There is no noticable change in engine performance. I took it to Auto Zone for the diagnostic. It came back as "P0420 Catalyst System Efficiency Below Threshold (Bank 1)". I called 2 Differnent Midas shops. Both of them told me that it means that either the catalytic converter is going out or I have a tank of bad gas (I refilled the night before the light came on). The midas guys thought it was very unlikely for the CC to be going out. They told me to clear the code and if it came back on, there is a problem. I cleared the code and within 20 miles of driving, the light came back on.

If this is due to bad gas, the problem may reoccur until I run this gas out. After this tank is gone, I am going to refill with high octane BP or Chevron, or something expensive as hell, and I may add a fuel system cleaner. I will run on this for a day or so and clear the code again, hoping it was just bad gas and that the light will stay off for this issue.

Does anyone have any input on this issue???? How can I diagnose the Catalytic Converter to see if it has any problems. Is there anything else that could cause this?

PLEASE HELP ME!!!!!!!!!!!!!

 
Rep Power: 453

first off why did you buy a car with no warranty?

But when autozone scanned your ECU, did any other codes come up?

More then likely your cat converter took a dump. there really isnt much testing with this code. Its either the cat is bad or not. Now more then likely it is bad because you already reset the ECU and the code reappeared. I dont think it is bad gas. And also putting higher octance fuel in there isnt going to help. You will be just waisting your money. You arent running higher compression or anything, so higher octane is going to be benifiting you. Dont ever let a shop tell you it is unlikely or too early for the cat to fail. especially midas. I will tell you like I tell everyone, parts fail at anytime. there is no mileage set for how long parts will last. If you had other codes with it, then it might still be functioning properly, but if not, you may need a new one.

Now in the service manaul it says to reset the ECU (pull the number 6 fuse in the under hood fuse box for 10 seconds) then reinstall. Then start the engine and hold it to 3000 rpm with no load in park untill the radiator fan comes on. drive for 10 minutes without stopping at various speeds. then drive for 30 seconds at between 50-62 MPH. Now repeat that whole process about 4 times, this insures that the car efficently warms up, and so the readiness codes complete. Now recheck if that same code comes back up after all of this? If it does, your cat took a dump. If it doesnt, more then likely you had an intermitent failure.

Now a new cat isnt cheap, a new one is around $600, but I am sure if you ask around on here, someone may be selling theres for cheap. Good luck.

 
Rep Power: 388

I just had this same code after filling up with gas and installing my new evo 2 exhaust mind you I have no cat. It was actually the gas cap thing and the sensor adjusting to the new setup...

 
Rep Power: 453

what does the gas cap have to do with the cat efficnecy? If your gas cap wasnt on tight, you would have thrown a code for a leak detected in the evap system. Now if you have no cat, then you will either throw a code for cat efficency or a code for the secondary 02 sensor not reading correctly.

 
Rep Power: 388

well there is the possibility to throw a cel for a gas cap not being sealed good enough, and the sensor was acting up due to the new evo2 exhaust and adjusted itself I guess

 
Rep Power: 0

The gas cap being off would generate a different code than P0420. Anyway, back to the lecture at hand. I have a 30 day return policy on the car, if I'm not mistaken. I will just bring it back and tell them to fix it, or I'll return it. I have only driven it for 5 days.

About not having a warrany: Honda warranty runs out after 36000/36 months. The car had 37000 on it when I got it. The dealer warranty would cost $4200. I didn't want to trade in an older car for a warranty. I'm hearing from other sources that this problem could be due to a bad o2 sensor as well. I will find out tomorrow when I take it back to the dealer. I'll update the site.

 
Rep Power: 0

I found this little document on the EPA website that may also play a roll in my case if the Cat is the problem. Here is the link. Other people may benefit from it as well.

EPA

For example:

 
Rep Power: 453

you dont have to buy honda extended warranties. There are several extended warranty companies out there who offer warranties starting at $1000 for complete vehicle coverage.

Now if the problem was caused by a bad o2 sensor, then you would have thrown a code for a o2 sensor. You threw a code for a cat converter below threshold. Basically meaning your cat may have tooken a dump. In the previous post I posted, I outlined the procedures to diagnose that code straight from the service manaul.

 
Rep Power: 0

Streetglower...

Quick question: The light turned itself off once the gas tank got low. I refilled and the next day it came back on. It initially came on the day after a fill-up. What would this indicate? What sensor tells the ECU to show a P0420? This gas company uses some fuel additives. Could this be an issue? I'm bringing it in later this week but am trying to arm myself with info. Thanks for your time.


For anyone else reading...YES THE GAS CAP IS ON!!!!!!!!!!
(10+clicks )

 
Rep Power: 453

What gas station do you fill up at out of curiosity? At first I didnt think that the gas was the cause of it, but I am now starting to take back that statement based on what you now told me.

The only thing I can think of is you might be using a station that uses bad gas or gas that sits too long and collects dirt and crap. that generally comes from mom and pop gas stations. Other then that I am not sure on that one.

The sensor that will monitor the cat will be the secondary o2 sensor. under normal driving if everything is working fine, the cat converter will reduce harmful emissions from the exhaust coming out of the engine. it will do it by using heat and special metals in the converter to reduce the emissions.

Now another thing you need to figure out is if you just started getting gas at this gas station, that might be the cause of the converter failing. Also your engine might be out of tune. Or third is it just failed. If the gas isnt the issue then make sure the dealership checks out the performance of the engine to see what might have caused it to fail. You dont want a new one to fail right away.

But first let me know what gas station you use? or what station you did you right before the light came on?

 
Rep Power: 0

The gas station is a major chain here in Louisville, and other cities, named Thorntons. http://www.thorntonsinc.com/ The good news is they preach up their gas so much that they offer a 100% guarantee stating that if any problem arises from their gas, they pay for the repairs. I have already obtained the needed contact info if this is the purpose.

Unfortunately, since I just got this car last week, I don't know what gas was consistantly put in it. I always use Thorntons in my other rides. I have put 3 tanks of gas in this car since I've had it, all Thorntons 86. The station I use is VERY busy and relatively new (2-3 years). I wouldn't think it was due to stagnant gas. Also, I asked the employees there if they had received any complaints. They said no. I believe, they use "Gasahol" as well.

Again, thank you for your time!

 
Rep Power: 266

very important- have you had any misfires before all this, and what condition are your plugs in? also do you have any exhaust leaks, im really tryin to help i got my sevice manual out and readin all kinds of obd2 forums

 
Rep Power: 0

Dude, you are awesome with the help. Regardless, I'm taking it in to the dealer tomorrow morning after work (night shift). I just got the thing 2 weeks ago and the dealer will handle, hopefully, most of whatever is wrong. There haven't been any misfires since I've had it. Not sure about the plugs or exhaust. I think it either needs a tune-up or has a bad rear O2 sensor. I'm not ruling out the Cat, but the way my luck is, it won't be anything under warranty such as for the emissions. Any info is appreciated!

 
Rep Power: 453

more then likely if you have a bad o2 sensor, you will throw a trouble code (check engine light). But even then the front one would be more likely to cause any issues.

 
Rep Power: 0

Confirmed this afternoon: Catalytic Converter

Replacement if FREE. Thank you guys for your help in trying to figure this one out!

 
Rep Power: 266

you were talking about gas you used, missfires [fuel in exhaust] is a major hazard to a catalyst, make sure the gas is completely burning in your cylinders, did they say anything about the old catalyst? injector/complete fuel system cleaner couldn't hurt- What kind of numbers are you getting for gas mileage?

I suspect it just failed for some very rare reason, but i just want to make sure it wont happen again.

 
Rep Power: 0

I didn't have any misfires. I was hitting around 400 miles per tank (only gone through 2 tanks though). The tank of gas in the car now has some STP fuel system cleaner in it. If the new catalyst system fails again....the issue will be pointed to the gas company and they will pay for the repairs.

 
Rep Power: 453

it would be nice to blame them, but it wouldnt be there fault. But you can blame the shop you fixed your car. If they didnt make sure everything else was working properly and didnt note any thing down on the repair order, they will be a fault. But parts do fail, and maybe the cat failed on its own. its possible.

 
Rep Power: 0

The shop that replaced the Cat is an Authorized Honda Dealer. Got the car today. Works fine with no CEL!