p0420 CEL

[98blackcivic]

finally got this...after much reading, this CEL likes to show up at any range of mileage...60K, 80K, 130K and 160K..
mine went off at 104K


after searching and searching,
im still confused if this CEL refers to the O2 sensor or CAT
bank 1, catalyst below threshold.


if anyone has had any experiences, let me know.
im ready to replace the entire emissions system but maybe its just a better idea to replace the thing thats causing the problem.

so what should i replace?

[project_EM1]

Po420 means the catalytic converter is going bad and not performing to specs. Replace the catalytic before it does any damage to the secondary o2 sensors, or you will end up having to replace that also. But I would start by replacing the catalytic converter first.

[98blackcivic]

yea i had run out of gas so i guess i fried my cat...
the honda cat is $1000
what would u guys say about the ebay ones?

also i ran out of gas because im stupid..in case anyone was wondering...

[98blackcivic]

2003 2004 2005 2006 2007 Honda Accord Catalytic Converter 2 4L 4CYL New | eBay (http://www.ebay.com/itm/2003-2004-2005-2006-2007-Honda-Accord-catalytic-converter-2-4L-4cyl-NEW-/190693146582?pt=Motors_Car_Truck_Parts_Accessories&hash=item2c66327fd6&vxp=mtr)


the one i want to buy

[green91]

There is no mileage interval that Catalytic converters go bad. The CEL can come on at any time it isn't performing to spec.

A bad catalytic converter won't damage the o2 sensors. The only time a bad catalytic converter can be a problem is if it becomes clogged which isn't common in Hondas.

Running out of gas won't damage the cat.

[l Gizzy l]

^^^^wambam. Look on Craigslist/honda forums for the cat. They'll be selling them for like ~$60.

Also if your O2 sensors are throwing a CEL, either the sensors are bad or there's a problem. If there's a problem then it will eventually foul out the cat.

[Bacon]

My wife's SUV has the same code. Replaced two sensors and the cat already. If you find out what caused it, let me know so I can fix hers.

[98blackcivic]

was just told by this junkyard that 'selling used cats is illegal'

dunno what to do...should i shell out the $660 for a brand new one?

[l Gizzy l]

fuck no. Go to an exhaust shop, have them spot weld in a cat they have lying around from installing test pipes, go get the emissions, then remove the cat and have it test piped.

<200 total.

[isa2o3]

My wife's SUV has the same code. Replaced two sensors and the cat already. If you find out what caused it, let me know so I can fix hers.

Did you use aftermarket ones?

[98blackcivic]

i dont want a temp fix.
to me its worth it to spend a grand to fix the entire emissions system if i have to.
i just dont like the 18-22 mpg that im getting as opposed to 28-30 before.

yesterday i cleared my CEL with the scanner...
ive driven ~50 miles so far and it has not come back.

[green91]

Unless the cat is clogged it won't affect your MPG.

[S4saken]

You said you don't want a temporary fix but using spark plug non fowlers to put the o2 away from the exhaust flow will get rid of your CEL and allow you to pass emissions. Your rear o2 has nothing to do with the performance or has mileage green91 stated above its just there to monitor the cat.

[PTCDC5]

I threw that code on my DC5 and first changed the o2, hoping the $200 sensor was the fix instead of the more expensive cat. As stated earlier, it's the cat that has failed. I would highly suggest a low mileage OEM cat instead. So much less hassle and less money than tracking down a decent aftermarket unit and possibly having fitment issues.

[00CelicaGT]

My wife's SUV has the same code. Replaced two sensors and the cat already. If you find out what caused it, let me know so I can fix hers.

OEM is the best option, especially on newer vehicles. most aftermarket converters are too small and the materials inside are cheap and generic, most people don't want to here this when the OEM is $500+ but its always better to replace with and OEM converter when u get a P0420. I see customers come through the dealership all the time that went the cheap route but anyways end up returning and spending more money on top of what they just spent at joe blow down the road.

If it was a weld on muffler U might want to check and make sure they didn't install it backwards, I see that allow too lmfao.

[Franco Tirador]

i had a code like that on my 99 accord 4cyl, (they are known for that) replaced the cat with one from autozone, came with 5 year warranty, and no more cel after that, only thing is autozone only warrties the cat, so if it goes bad within 5 years you have to take if off the car and take it to them so they can give you another one, or buy it again, then take the one you took off the car (the first one you bought from them) and they will give you your money back

[silversol]

fuck no. Go to an exhaust shop, have them spot weld in a cat they have lying around from installing test pipes, go get the emissions, then remove the cat and have it test piped.

<200 total.

Good luck finding a shop to do that! That is up to a 10k fine for that shop!

[NOCLUE]

mine went bad, bought a magnaflow off ebay BOOM works fine passed emissions