LLimited12

Just wanted to update and say that it is indeed a O2 sensor. After reading about the ‘Bank 1,’ code, I ruled it out and it did solve the problem. You guys are awesome! My bank account and myself are very grateful

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I have had code 0420 on other cars. The reason it take some miles for the code to reappear is that ECM has to detect the condition for 3 times in row. In my case of my 3 cars, the rear O2 sensor was faulty in everyone of them. 2 of the cars were just over 100k, the other was 125k miles.

 

 

 

Someone needs to diagnose the issue. Advantage Auto parts isn't. Looking at the Subaru diagnostic table, most of the diagnosis is either data logging and looking at the rear O2 sensor wave form or using multimeter to check continuity and resistances.

Subaru is who diagnosed it the 2nd time. They never mentioned the 02 Sensor maybe causing the issue. It very well could be, though.

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I was talking about your torque converter you say is failing.

 

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The TQ is covered.

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What trouble code(s) are you getting? If you unplug the battery to reset the ECU, how quickly does the code come back? I'm not sure how a non-reactive cat would affect mpg at all, but I wonder if a bad O2 sensor would. Catalytic converters need a rather narrow af ratio to function and not go bad, so even if your cat has gone bad, I would wonder if there was a more interesting reason for it.

 

 

 

Assuming you do need a new cat, I would suggest getting an OEM cat off of ebay and installing it, that sounds legal. It would be cheaper to get an after market direct fit part and have it installed with the OEM heat shields. It would be even cheaper to have just the old cat cut out and replaced with a universal one and have them try to fit the heat shields back on over it. IMO all these are pretty environmentally friendly. All of these would be more reasonably priced than going to the dealer.

 

 

 

 

 

 

 

I don't want to debate reliability, the statistics are out there if you want to look at facts vs hearsay. I will say that it is an interesting tactic to trash talk Subarus on a Subaru forum where you're asking for help.

I haven’t tried resetting the codes on my own. I plan on going to Advance tomorrow to have the code reads again and cleared. The first time they did it, everything was fine for roughly 60 miles. When Subaru checked the codes, it didn’t reset them. (Or so I’m assuming.) There is also a leak in my gas cap. Again, I’m not sure if that would cause all of these codes.

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If your car is a PZEV vehicle, there should be a 15-year, 150,000 mile warranty on the emissions components.

 

Usually just throwing a code is not enough to say that a cat is faulty. The cat is just one of several possible causes for "catalyst efficiency below threshold". A bad cat normally does not affect gas mileage by 6 mpg, and it's unusual for cats to go out on cars with similar age or miles. Other possible causes are things like bad sensor, faulty wiring, exhaust leak. The technician should run through the diagnostic routine in the factory service manual to rule out the other possible causes before declaring the cat is bad.

The car is PZEV. I’ll be looking more into this. Thanks.

Edit: That warranty only applies in a select few states. Virginia is not one of them.

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You have an extended warranty use it...

 

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Extended warranties won’t cover CC’s.

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It’s funny, the man who worked on my car said I should get rid of it as soon as I can. He said that he sees more Subaru’s come in for work, normally little things - annoyances - than he does FCA products. Typically all over 60K miles. That is more than likely the route I will go. My TC is going too, which will cost around $5,000, or so I was told. Buying a new car just seems like the best route to go.

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Can you tell us what is the mileage, model and year of your car? Where do you live?

 

Some of the emissions components are covered by a long warranty period by law.

 

How do you know you need a new cat?

I live in Virginia. My 2012 Legacy 2.5i Limited has a little over 101,000 miles. I know that it needs a new cat because that’s what the code read at 2 different places, including a Subaru Service Center. They tested the emissions to make sure and it failed. I’m also getting about 7mpg less than what I normally do.

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For that much you can get an aftermarket exhaust (600), with a cat (200) and installed (300)

 

 

 

or you can go to a muffler shop so they can put in a $200 cat. you may need mechanic to put something in to prevent CELs though.

I have extended warranties on the car that forbid the use of aftermarket parts on any part of the car other than wheels, headlights, bodywork, etc... Failure to obide results in me being out over $3,000 and no warranty.

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It doesn't seem like catalytic converter failures are very common for 5th Gen's. How many miles are on your car?

101,200 miles. 2012 2.5i Limited.

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Has anyone had to replace their catalytic convertor? Mine is shot and the dealer wants $1,100 to fix it. I have an extended warranty that doesn’t cover jack shit, so I can’t get it fixed because I don’t have that kind of money laying around. Should I only go with geniune subaru parts or can I get by with a high quality aftermarket part?

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