code question

RedForester08

RedForester08

New member
I'm getting code PO420 twice now. Catalyst System Efficiency Below Threshold Just bought the car. It was sitting for a few months. Will this trip this code sometimes? I first got 10 miles down the road. reset it then 115 miles down the road. any suggestions? just checking to see if anyone has had this cat. issue.

 
all subies have this issue weak cat. system.if you look at any reveiws on most subaru's that's one of there weak points and its like $900 or so through the dealer to get repaired.but i would start by changing the front o2 sensor.my wrx was doing the same thing but it has a brand new catted downpipe.so i replaced my front o2 sensor and have had no cel's since

hope this helps

 
2001 Forester 88210 miles. It had one of the O2 senors changed awhile back. Say's here a

PT260704 F Oxygen (A/F) S

Is that the front one?

 
so would that be the one that sees what the cats are doing? I'm going to replace that one as it is still factory and see what happens.

 
Update on my situation on my cats. Well called the previous owner about a CEL when she traded the car in. She said yes it was on with the PO420 code. She then told me she had her local garage put in a new cat unit. ( after she brought it to the Subaru dealership first) and that the light always came on after that. This was may of 2006. She had only 78000 miles on the car and the Subaru dealership said that they can not cover it because the local shop had cleared the code. (prior to her having it fixed). So I looked under the car to see and It is hard to tell. The midpipe says Subaru on it. The cats are still a one piece unit but with no shields wrapped around them and the pipes. Just a small shield on top and no Subaru makings on them. The rear O2 sensor looks to be the original with the red wrapping and flex wrapping it the middle and no splices anywhere.The wire is just kind of floating around and it has two clips on it that are not hooked to anything. does anyone have a pic of the stock system to look as a reference.

Thanks

 
Well got the dealer I bought the car from to pay $400 towards this problem.
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So I said fudge it and replaced both the cat unit and rear sensor with OEM parts new gaskets and so on. :'( The after market cat unit that was on there looked as old as the rest of the exhuast. The flange bolts where half way rotted off. So I just cut them with a sawz-all. There is no way that thing was just changed 1 1/2 years ago. The sensors came out without a hitch. Also Starky Ford had put 5W-20 oil in it about 500 miles ago. ??? (where the car was traded in not where I purchased it) and a motorcraft oil filter. Now that is no way to treat a Subaru. >
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So I put on a OEM filter and some 5W-30 Amsoil in it and boy don't that thing run smooth now. The motor runs and sound just like my 07 Impreza. minus the Prodrive and the improved power of the MY07. You guys know what I mean. It sounds and runs like it has 20k for miles not 88k. So in my opinion sometimes going with cheaper will cost more in the long run. It is a real easy job for the most part.

Thanks to all with the advice and of course to the all mighty parts goo-ru Joel. 8)

 
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