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2013 OB Limited 3.6R
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30 Posts
Discussion Starter · #1 ·
I have a 2005 Outback h6, I'm the second owner (bought at 58K miles, now has 92K miles). I change the oil every 3K miles (have free oil changes from the dealership), and I have an extended warranty- which covers everything that wouldn't normally break.

We did a road trip last month (1400 miles) and at some point the car was very low on gas and started stuttering, so I pulled to the side before it ran out totally. One great Wisconsinite provided me gas in a canister which was probably less than a gallon, and it took me to the gas station. I had a CEL right after that, and I assumed some dirt got to the injectors and it was a misfire. After couple drives it went away- only to come back at random times. At some point last week, the breaks went stiff (like the vacuum is lost) and the engine seemed like it was having a hard time breathing (exhaust clogged?). Both problems were intermittent. The car accelerated great on the next drive.

I took the car to the dealership yesterday, and they read a 420- which meant replace all catalytic converters in their books- a mere $3050. I love the car but 3050 for a car that's worth 12K is a little steep. So I took the car to another shop (mufflers4less :). Tech said he can cut the pipes before and after the converters, install aftermarket converters and plug the sensors back in. However he can't do anything for the 3rd converter which is where 2 pipes connect. (total cost $500)

I looked around the forums and I can't seem to find anyone who can pinpoint the actual problem. I checked OEM converters, they retail for 700+ and 800+. I found another brand- davico that retails for 375-241.

My main question is- what could be the problem- sensors? converters? misfiring cylinders? (I thought that would throw another CEL code). I found couple posts which describe how to check sensors for signal- but I don't think I can get under the car to check it that way. I don't want to throw 500 and replace the original converters with aftermarkets only to have the same problem in a month.

Sorry for the long post- thanks in advance.
 

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Premium Member
(formerly) 03 H6 OBW , (presently) 06 WRX Sportwagon & 2021 Honda CR-V
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18,647 Posts
is the car running poorly now?

If not, I'd have any codes read, noted, then cleared. (often, an O'reilly's or AutoZone will do this at no charge)

While you're at the parts store, buy a can of SeaFoam. Use it in a full tank of gas. (read the label - it may be 1/2 can.)

monitor how long it takes for the CEL to come back on, go to the parts store, have the codes read, post them back here.

sometimes, sensors get lazy or other 'small' problems crop up and set codes that can be associated with very expensive items. I doubt your cat conv. are bad - but there may be an exhaust leak, clogged fuel filter or a bad sensor or vacuum leak, etc.


If the car is not running well, you will definitely need to do more troubleshooting. If you are not an auto DIYer, someone may be able to direct you to a good mechanic in the Chicago area that won't just throw cat converters at your car unless absolutely necessary.
 

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2013 OB Limited 3.6R
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30 Posts
Discussion Starter · #3 ·
Thanks Lucky Texan,
The acceleration is poorer than normal, other than the one time brake issue, I didn't have any major problems.
the fuel filters on these cars are inside the tank, and they are "not servicable".
I use fuel injector cleaners every 6 months.
How can one find if there is a vacuum leak / exhaust leak? I don't hear any noise from the exhaust, and under the car it didn't look too rusty (given the winters and salty roads of chicago)
I thought about trying the seafoam, but I can't find the pcv valve on the h6. I'll search for that.
I agree that the cat converters are not the problem. Even if they are- there should be an underlying problem that caused them to go bad, and without fixing those I don't see much point in replacing anything.
 

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Premium Member
(formerly) 03 H6 OBW , (presently) 06 WRX Sportwagon & 2021 Honda CR-V
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you can use the seafoam in the tank but, if you have used some other similar product since the 'borrowed fuel' problem occured, I doubt it will help.

the borrowed fuel may be a red herring so, you can't discount some other issue. You need to find out if there are codes stored other than P0420. With the low power issue you're having, seems like there's be other codes. A car parts chain store should be able to scan for set or pending or stored codes. note them and have the CEL cleared - monitor how quickly it returns.

the P0420 (and many other codes) can be tricky to diagnose and cure. If the car weren't exhibiting other problems, I might suggest an 'anti-fouler' fix for the rear O2 sensor. It is the one responsible for triggering a 420 code and some folks use 'tricks' like a spacer to get around it's annoying sensitivity.

if you have a warranty - even paying a little deductible or renting a car may be worth it to force the dealership to fix the problem. They may even re-program the ECU to be less sensitive or ignore the rear O2.

maybe I'm confused by your original post - but you seem to understand that it's unlikely the cats are bad - if they want to replace them at THEIR expense, they're foolish but - the 420 problem should be well documented and if it comes up again, just take it back to them.
 

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2013 OB Limited 3.6R
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Discussion Starter · #5 ·
Maybe I wasn't clear- the warranty (easy care- total care) does not cover catalytic converters. I checked the original Subaru coverage, and the emission is covered upto 80K miles. (really hard to find- but I found it at mysubaru.com). If it was covered I'd have the dealership change the converters, but currently they are expecting me to pay $3050.

also I never used seafoam, but I'll try some today. I found the PCV valve thanks to opposedforces.
 

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2013 OB Limited 3.6R
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Discussion Starter · #7 ·
I took my car to another shop, and the verdict seems to be the same- the cat converter needs to be changed. This shop said the bank1 seems to be the problem, so he offered to change both converters, but he said I only need bank1 to be changed. He said I should use subaru OEM, anything else will cause issues, because the car is too sensitive.

Has anyone had any experience with Davico aftermarkets? they are direct fits, and I'll get the gaskets from subaru. The OEM prices run around 800, while the davico is around 300. It also has a warranty (although I need to check what the coverage is)
 

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2013 OB Limited 3.6R
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Discussion Starter · #9 ·
I tried seafoam (2.5 oz thru the PCV hose using a baby bottle)- the neighbors thought my car caught fire and panicked. it was kind of embarrassing to fume the whole block. I also tried to see if I could unscrew the PCV valve, but non of my socket wrenches were able to get a good grip. I'll take it to the dealer (they already charged me $120 for diagnostics, which I should be able to use for service) to change the PCV valve. The reason I'm inclined to think it's the PCV is 1- because it's cheap :), 2- because the problem is intermittent. If the cat converter was plugged, I'd have a choked engine all the time. My engine runs smooth at times, and choked at other times. I translate that to a sometimes-stuck PCV. If it's not the PCV, well- I'll keep on looking at other places until I run out of options.
 

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OBW H6 VDC, Tribeca, XT6
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P0420 is almost never, ever, a bad converter.
+1
you can ignore the P0420 because it's for the rear O2 sensor which has nothing to do with drivability, the ECu doesn't even use it. it is only a monitor and all it does is cause that 0420 code to pop up, that's it. you can remove that sensor completely and the car will run indefinitely with no issues.

if you want to get rid of the code:
1. clear up any exhaust leaks if any
2. install the $5 spacers and be done with it.

replacing the converters is a %100 waste.

Subaru originally had a 2005 Catalytic converter related recall though it appears they changed the wording...here's an example:
http://www.subaruoutback.org/forums/66-problems-maintenance/21123-recall-notice-wvm23.html
 
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