P0420 code!

[Grimmrican]

Hey guys just last night while I was driving to the store my CEL turned on! I'm irritated by it. Anyways today at work I thru the scanner tool in the car and error code
p0420: catalyst system efficiency below threshold (bank 1)

Now I've had the car for over a month now and no problems whatsoever ( 00 BE) I recently installed some eBay UEL headers (about a week now). Can the headers be the cause of the CEL?

[Huffer]

How many miles on the O2 sensors and catalytic converter?

UEL headers can contribute to these errors, but normally they're due to the pre-cat O2 sensor going bad.

[GTDrifter]

Toss on a sensor spacer and call it a day

[Grimmrican]

Toss on a sensor spacer and call it a day
How legit is this?

[Grimmrican]

How many miles on the O2 sensors and catalytic converter?

UEL headers can contribute to these errors, but normally they're due to the pre-cat O2 sensor going bad.
Eng has 182k on it and to be honest I doubt they were ever replaced. All I know is this is gonna kill my gas mileage lol but it hasn't yet. I cleared the code and I'm gonna take it to RI later after work. Hopefully the CEL will stay off. Fingers crossed

[Felipe]

have you change your oil or checked you spark plugs?

search in diy forum for "P0420 fix" i posted a link to a video that shows you how to help it go away.

[Grimmrican]

have you change your oil or checked you spark plugs?

search in diy forum for "P0420 fix" i posted a link to a video that shows you how to help it go away.
Ok thank u. I was actually thinking it might be kuz of an oil change or the headers. I looked at the oil today and that shit was as black as black gets. Can u post a link?

[oncesir]

Toss on a sensor spacer and call it a day

My BD LGT needed 2 spacers, aka spark plug anti-foulers, to remedy the p0420 code. It went away forever though. Probably still like that today. Lol

Sent from my PG86100 using Tapatalk 2

[Grimmrican]

Toss on a sensor spacer and call it a day

My BD LGT needed 2 spacers, aka spark plug anti-foulers, to remedy the p0420 code. It went away forever though. Probably still like that today. Lol

Sent from my PG86100 using Tapatalk 2
I think it's funny that it reads bank 1. But doesn't say what sensor. There's only one bank on the car lol. Anyways I know at aap we sell foulers I never knew wtf they were for. I'll grab them tomorrow. Thank guys

[chuckthefuk]

Funny no not really.. Using a generic code reader will always default to the OBD2 generic diagnostic system programming that has been used across all major auto manufacturers since 1995/6+

So to sum this up the code reader doesn't really know its a subaru.. its just reporting OBD2 PID values. And P0420 PID generates the generic "bank 1 " message.

If you purchased a higher quality unit it would report (bank 1 sensor 2)

Sorry to be a party pooper. I am on a OBD2 kick right now.

[Grimmrican]

Funny no not really.. Using a generic code reader will always default to the OBD2 generic diagnostic system programming that has been used across all major auto manufacturers since 1995/6+

So to sum this up the code reader doesn't really know its a subaru.. its just reporting OBD2 PID values. And P0420 PID generates the generic "bank 1 " message.

If you purchased a higher quality unit it would report (bank 1 sensor 2)

Sorry to be a party pooper. I am on a OBD2 kick right now.
Damn i don't think my job has a more expensive obd2 scanner? We have the one that's like 250$ does the job I guess. But I understand what it saying as well.

[chuckthefuk]

Well there's this.
https://sl-i.net/FORUM/images/imported/2013/03/200967114234758-2.jpg

then there's this
https://sl-i.net/FORUM/images/imported/2013/03/tumblr_mhuimp0yuN1rgp5auo1_400-2.jpg

and there's this bad boy right here
http://img571.imageshack.us/img571/4558/img20130124182549.jpg

I use the fancy one sometimes which has more diag features compared to just scanning. It can program VINs/Immobilizers and test on/off sensors and show misfire counts.. so much goodness in a fancy box
-Chuck

[Grimmrican]

My jaw dropped on the last one lol. Looks similar to what garages use

[chuckthefuk]

Thats exactly what garages use :-D

I am very fortunate to be friends with many mechanics.

[Baddog]

Use the foulers that are the shape of an "L"

[Bhatman]

Thats exactly what garages use :-D

I am very fortunate to be friends with many mechanics.

If I were you id look into Subaru SSM. Its an open source OBDII reader/tuner/scanner. I grabbed an OBD II to USB cable, installed the program on my laptop (Goes on Windows,Linux) can check codes, Throttle, Transmission and reset them too. Hop over to subaruoutback.org and there is a whole thread dedicated to the opensource program.

Also for the PO420, id reset the code, see how long it takes for the code to come back. Were entering the switch between winter and summer blended gas and the Cats, especially on BHs and BEs have a tendency to be picky. The fouler will work, just make sure its on the post cat 02 sensor. While your at it, check your 02 sensors and see if there gummed up.

[chuckthefuk]

Hmmm.. I think you mean Subarus SSM protocol that can be used with FreeSSM or others.. But the main issue is

"FreeSSM is a free and easy to use diagnostic and adjustment tool for SUBARU vehicles. It provides access to the engine and transmission control units of the models Legacy/Liberty, Outback, Baja, Impreza, Forester and Tribeca (not before MY1999)."

So like many others this doesnt work with the older ECUs..

I found a few alternatives but none seem to be user friendly
http://www.alcyone.org.uk/ssm/software.html

Still cool but not that useful for Gen 2's..

-Chuck

[Huffer]

You guys are completely missing the point I think.

The guy has an engine with 182k on it. And UEL headers.

So, he needs (in this order):
2 new O2 sensors
probably 1 new catalytic convertor
maybe a rear O2 sensor spacer

[Grimmrican]

I actually think its the o2 themselves. I doubt no ever changed them so ill just start there and hopefully that should do it but ill look into all the other info as well. Thank guys

[Bhatman]

You guys are completely missing the point I think.

The guy has an engine with 182k on it. And UEL headers.

So, he needs (in this order):
2 new O2 sensors
probably 1 new catalytic convertor
maybe a rear O2 sensor spacer


Point taken though it would be more of:

Spacers
02 Sensors
New Cat

In that order (cost-wise) :smile:

Since the SSM program works well with BH's and BE's I threw that up there. Hopefully the overall diagnosis stops at sensors...since Cats are pricey.

[Grimmrican]

Tell me about it I bought a cat system for 189$ off eBay and its both the cats together. Aap wanted 500$ my eyes crossed and I shit myself when I saw the price lmao

[TheGr8Ox]

Your lucky, for those of us unfortunately to live in California, we have to have very specific converters, the cheapest I got front and rear was $530, that of course is for direct bolt ons, shops in my area wanted a minimum of $800, I said hell no!

[unsullied_spy]

Tell me about it I bought a cat system for 189$ off eBay and its both the cats together. Aap wanted 500$ my eyes crossed and I shit myself when I saw the price lmao
New ones from the dealer typically have a comma in the price :shock: Usually best to find a decent used one and toss that in. Or do what I did and buy a wrecked car and part the thing out. I took the engine, traded the transmission for the labor, then the rest of the parts went into paying off the cost of the wrecked car. Basically got paid to put a new engine in my car.

While you have the exhaust dropped to put in the new cats put one of those non-foulers on the rear o2 sensor. Cheap insurance that you won't get a catalyst efficiency code any time soon. With that mileage it may not be a bad idea to buy a new A/F sensor though. They're spendy but it will wake the engine up and likely pay for itself in increased MPG--also makes the car less likely to toast the cats again.