Check Engine Light: Code P0420??

my 06 legacy check engine light came on for the 3rd time in 6 months, 1 time was the o2 sensor, next time apparently the maf wires were loose and a few others too that were causin a low voltage... this last code just showed up:

 

P0420

catalyst system

efficiency below

threshold (bank 1)

 

any ideas on what it might mean. My friend was able to reset it with his cobb accessport. which is bad ass btw. the light hasn't come back on but it might be only a matter of time.

me thinks that means your cats are not working as good as they should ,,

02 sensor?

you need a new cat convertor there going quite often in the n/a subies

wow i hope not... i just hit 37k .... no more w arranty on the car... grrrrr:spin:

I believe the cats are covered under warranty up to at least 60 thou maybe more.

It is a catalytic converter code. They are covered under the 8/80k if it is not PZEV

Do you have aftermarket headers or a high-flow cat? P0420 is VERY common on N/A cars with those mods. If not, then yes your forward O2 sensor is probably bad, or perhaps the cat.

And if you have a bad sensor you may toast the cat since it can get too much to take care about. Same is if you have injectors that are bad and needs cleaning.

Take it to the dealer its under warranty. Very common.

yea, no reason that shouldn't be covered under warranty.

i have no mods done to the car yet. its just wierd in 5 months i have had 3 check engine lights all for different things.

 

even tho my 36k mile warranty is up, it should still be covered?

i have no mods done to the car yet. its just wierd in 5 months i have had 3 check engine lights all for different things.

 

even tho my 36k mile warranty is up, it should still be covered?

 

It is a catalytic converter code. They are covered under the 8/80k if it is not PZEV

^^Right, should be covered.

 

Here's something to consider...

 

When I bought my '00 RS, there was a service bulletin, #WXW80 I think. I got a CEL about every 10K miles up until 60K. Basically my O2 sensors kept burning out. The factory kept replacing them for me though, because of the coverage.

 

Turns out the engine was running too rich due to some ECUs having a bad program. So SoA issued a reflash bulletin for EJ251 engines within a certain VIN range. My car was NOT in the range, but they did the reflash anyway. It fixed the problem.

 

I wouldn't think that there may be a similar issue now, but I could be wrong. So check around for service bulletins (TSBs). The dealerships should have a list. You can also register on http://my.subaru.com and it should tell you if there's any open recalls.

^^Right, should be covered.

 

Here's something to consider...

 

When I bought my '00 RS, there was a service bulletin, #WXW80 I think. I got a CEL about every 10K miles up until 60K. Basically my O2 sensors kept burning out. The factory kept replacing them for me though, because of the coverage.

 

Turns out the engine was running too rich due to some ECUs having a bad program. So SoA issued a reflash bulletin for EJ251 engines within a certain VIN range. My car was NOT in the range, but they did the reflash anyway. It fixed the problem.

 

I wouldn't think that there may be a similar issue now, but I could be wrong. So check around for service bulletins (TSBs). The dealerships should have a list. You can also register on http://my.subaru.com and it should tell you if there's any open recalls.

 

Those recalls were related to the ecu and front O2 and they offered a reflash for them as a recall and some had to get an oxygen sensor.

 

His case is different but the technicians can still pull up tips and bulletins if the diagnosis doesn't lead them to a bat cat.

 

Some vehicles that were not affected by the recall can still have that work done to address a concern, but it won't be a recall nor could it be free. Case in point, the older Legacy Outbacks 2.5's in the late 90's had an axle seal recall. Well they do not come with axle seals but they still can leak in that area. So we still make the same repair on all models and install seals, because that recall was known to fix the same problem even though the newer ones don't have that recall.

Precisely. So do what I did, and call SoA and have a case opened. They'll work with the dealership and help you.

There is no need to call SOA. Let the dealer diagnose the issue and replace what is wrong, as it is cut and dry. All SOA is going to do is call the dealer and ask them what is wrong with the car and they will tell them. Nothing really will get accomplished by calling them.

 

Now, if they feed the customer some kind of bs and try not to cover it(allow the dealer a chance to diagnose and fix it first), then contact SOA and get them involved.

is there a way of pulling up the code with out the comp

There is no need to call SOA. Let the dealer diagnose the issue and replace what is wrong, as it is cut and dry. All SOA is going to do is call the dealer and ask them what is wrong with the car and they will tell them. Nothing really will get accomplished by calling them.

 

Now, if they feed the customer some kind of bs and try not to cover it(allow the dealer a chance to diagnose and fix it first), then contact SOA and get them involved.

 

Right, call them if there's a problem. Often times dealers will give you the runaround.

is there a way of pulling up the code with out the comp

A scantool will just pull codes. The Subaru Select Monitor will also run freeze frame info and check how the engine and ecu is currently reading. The SSM will do a lot more than what a scantool can do. It also depends on what type of scantool you have. Unless you are spending over $250-400 you are just getting the basic code reader.

Just go this CEL today. Here is the situation: Went stage II (MKS cat-less down pipe and V1 Ap) about a month ago. Was running COBB stage II 91 octane for a tank of gas and everything was fine. Last night filled the tank and flashed the Economy base map to see if I could get a little better gas mileage since it is still my commuter car. On the way home today I got the steady CEL and flashing cruise light, looked up the CEL with the AP and found this code.

 

Do I have a bad O2 sensor (front or back)?

 

Are my other two catalytic converters going out?

 

The car is an 05' MT LGT. I got it used last May. I know that it should still have the power train warranty but have yet to try it.

 

I need some help guys!

in your economy base map you probably didn't have that check engine light turned off .. for cat below effeciency or some thing on those lines..

I'M HAVING THE SAME PROBLEM. the samecode comes up for me when i went 2 autozone 2 get it checked out.i reset the code disconnecting batt. but comes back on? i had the dealer reprogram the cat. converter free of charge due 2 a letter they sent me bout the faulty cat. recall issue? PLEASE HELP ME. because right now i'm broke ass hell n unemployed.GREAT TIMING RIGHT. I LOVE MY LEGACY but its stressing me out!!!

I just put headers up pipe, same code. Reset with Ap we will see what happens!

I'M HAVING THE SAME PROBLEM. the samecode comes up for me when i went 2 autozone 2 get it checked out.i reset the code disconnecting batt. but comes back on? i had the dealer reprogram the cat. converter free of charge due 2 a letter they sent me bout the faulty cat. recall issue? PLEASE HELP ME. because right now i'm broke ass hell n unemployed.GREAT TIMING RIGHT. I LOVE MY LEGACY but its stressing me out!!!

Maybe your cat is bad and that is why it keeps coming back.