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Subaru Crew Problems & Solutions

19283 messages,  Last post on May 01, 2013 at 9:15 AM

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What is this discussion about? Subaru Impreza, Subaru Outback, Subaru Forester, Subaru Legacy, Coupe, Sedan, Wagon, SUV


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Messages Page 1915 of 1929

#19140 of 19283 Here we go again... CEL Code P0420 by pathtomax

Jun 02, 2011 (11:20 am)

Hello again...just went my 2001 Outback (144,000 miles) was up and running again, the Check Engine Light comes on. As you probably remember, I had the Radiator, Water Pump, and Head Gaskets replaced about 2 months ago.
 
They notified me at Subaru that the P0420 code is that the catalytic efficiency is below the threshold. Estimate for repair $1,055.
 
So, my questions:
1.) Can I get this cheaper anywhere else?
2.) Can I just continue to drive *and feel horrible about hurting the environment*
3.) Should I just buy a certified 2008/2009!

#19141 of 19283 Re: Here we go again... CEL Code P0420 [pathtomax] by colin_l

Jun 02, 2011 (2:51 pm)

Replying to: pathtomax (Jun 02, 2011 11:20 am)
You ABSOLUTELY can get a qualified, independent exhaust/muffler shop to do re-do the exhaust from the headers back for far cheaper than $1,055.
 
They would use a/an generic catalytic converter(s) and weld up exhaust pipe. They would expend far more skilled labor, but it would cost less.
 
Why?
-O2 sensor, $75ish (could be as much as $100, could be as little as $40)
-2.25" (estimated) in/out catalyst, $200ish
- galvanized exhaust pipe, $100ish
- generic muffler, $60ish (if necessary)
- labor, est 3 hrs $65/hr, $195ish
 
$650 is my bet on a competent, privately owned exhaust shop.
 
DO NOT go to Midas, Rapid Muffler, etc. They are largely untrained and they don't care. They're just like the dealerships for the most part, bolting on overpriced OEM made-to-fit parts.
 
PS, you might just start with replacing the O2 sensor. It's fairly easy other than they can get stuck, but if you remove while the exhaust is hot they usually come right out. At 144k, such things are not uncommon. The catalyst could be done, too, and that's my assumption above.
 
Hope this helps!

#19142 of 19283 Re: Here we go again... CEL Code P0420 [pathtomax] by girlcarbuilder

Jun 02, 2011 (4:39 pm)

Replying to: pathtomax (Jun 02, 2011 11:20 am)
Yup, just did this one on the 2003 Impeza. Jacked up whole car onto blocks, dropped the whole exhaust. Dragged it out from under car. Bought new system with new O2 sensors. Assembled new system on ground and then dragged it under and hung it back up. Spent about $500 at rockauto.com and a few hours of my labor. Oh, have antiseize handy for exhaust manifold studs and O2 sensors. Get a new set of exhaust manifold gaskets as well. I prefer not to weld a system. That way I can replace individual components as needed later on.
 
I hope you are past head gasket problems, because antifreeze and cats do not get along.
 
On the 03, the state of MO forced the repair to finally happen. Something about thou shalt not drive and pollute at the same time or thou shalt not get safety sticker and license! I opt for number 2 until they force me to do something! You get the final call on that one though! 144K? 03 made about 250K. Maybe because it is a highway unit.

#19143 of 19283 Re: Here we go again... CEL Code P0420 [pathtomax] by xwesx

Jun 02, 2011 (5:09 pm)

Replying to: pathtomax (Jun 02, 2011 11:20 am)
Assuming the cats and oxygen sensors were not fouled by antifreeze, there's a good possibility that there is nothing really wrong with the cats. My car threw that code intermittently for years, yet the emissions inspections never noted any increase in exhaust "pollutants." In fact, the first inspection after that code started throwing actually yielded better results than it did two years earlier!
 
Of course, had the CEL been active, they would have failed it for no reason other than that. The nice part was that it would throw the code, I would reset it, and then it would usually be quiet for a week or two before throwing again. That way, I could "get away" without fixing the elusive problem, if it was a problem at all.
 
I think you should just keep the code cleared and sally forth as is unless your fuel economy is noticeably poor. If that's the case, then you probably have an issue with the oxygen sensors not giving good feedback.

#19144 of 19283 Re: Here we go again... CEL Code P0420 [pathtomax] by fibber2

Jun 06, 2011 (5:41 am)

Replying to: pathtomax (Jun 02, 2011 11:20 am)
I’m very much in Wes’s camp on this one. Look in any automotive forum on the web (including this one), and I’ll bet the number one CEL issue out there relates to the rear-most (#2 or #3) oxygen sensor. And unfortunately, many are too willing to plunk down $750-1200 on a quick fix, and wind up back on the boards complaining that the issues returned a few months later.
 
A P0420 is as you said - low cat efficiency. Basically, it indicates that the cat cannot burn off all of the remaining fuel in the engine exhaust. But the rear sensor is just a monitor, and nothing more. Unlike the front sensor that actually feeds back to the ECM to adjust fuel mixture, the rear sensor is simply a tattle-tale. You got that code because at some instance in time, the sensor’s voltage output was too high.
 
I’m a firm believer in spending a little up front on proper diagnostics, or at least trying the least invasive part swap first, before jumping to replace a cat. The code is an indicator of some type of problem, but what? Was it a one time event, or is this a steady-state problem? Is the cat failing, or just slightly degraded? It the sensor fouled, or just slow to warm up? Is there a wiring problem? An ECU issue?
 
What if, as Wes suggested, you cleared the code and kept driving. Would it return, and if so, how soon? Along with the error code there is a report on the activity of around 20 other sensors stored at approximately the same time (within a few hundred milliseconds). This is known as the snapshot or freeze-frame data, and it tells a lot about the conditions that induced the error. These cars use the old ISO protocol, so the data stream isn’t perfect, but, for instance, the log might show that this only happens for the first seconds after transitioning from open to closed loop operation (a warm-up issue). Possible diagnosis – the internal heater on the B1S2 sensor or wiring to it is bad, and the sensor is just a bit slow to come up to temp. Once warm, everything is fine.
 
Did the dealer do a real-time scoping of the continuous data output? Is the sensor always out of spec? How about a tailpipe sniffer? Is there lots of unburned fuel, or is it squeaky clean?
 
I can get into a lot more detail on this if you are interested. A single code means absolutely nothing unless you have data to go with it. It’s just the beginning of the search, not the end result. Don’t drink the Kool-Aid, at least not yet!

#19145 of 19283 Thanks for the help---- went with Certified Pre-Owned by pathtomax

Jun 06, 2011 (1:32 pm)

Hello everyone,
 
Thanks AGAIN for so much help. The CEL has been intermittently going on and off the past week. So, I did a little shopping online and found a good deal (in my eyes).
 
They are taking my 2001 Outback Ltd with 145k... and I am getting a 2008 Outback 3.0R LLBean, 36k miles, with Nav (that I didn't actually need).. out the door- $20k.
 
I think it was a great deal... Deep Bronze color and LOVE the LL Bean seats too! It comes with winter tires and I complained about how loud they were driving it in JUNE...so they are throwing in brand new tires too.
 
Deal...or no Deal.. LOL

#19146 of 19283 Re: Thanks for the help---- went with Certified Pre-Owned [pathtomax] by colin_l

Jun 06, 2011 (1:48 pm)

Replying to: pathtomax (Jun 06, 2011 1:32 pm)
Ouch, that sounds kind of like you got maybe $3k in trade-in value for your OBW and paid full retail ($23k) for the '08 3.0R LLBean.
 
However... the price of no longer worrying is definitely something. Enjoy your new ride!

#19147 of 19283 Re: Thanks for the help---- went with Certified Pre-Owned [pathtomax] by fibber2

Jun 06, 2011 (6:00 pm)

Replying to: pathtomax (Jun 06, 2011 1:32 pm)
I'm glad to hear that things worked out on your end, but a little bit disappointed. Now we'll have to go thru all of this once again about 3 weeks from now with some noob that found a great deal on a moderately used '01 OBW with this odd cat code problem!!
 
(Note to self: Make copy of above post for replay later...)

#19148 of 19283 Re: Thanks for the help---- went with Certified Pre-Owned [fibber2] by pathtomax

Jun 06, 2011 (7:07 pm)

Replying to: fibber2 (Jun 06, 2011 6:00 pm)
No worries on my end..., and I wouldn't consider a 144k, rust-spotted, dashboard cracked, sunroof leaking and a constant squeaking noise that no Subaru professional could figure out... 'moderately used'

#19149 of 19283 Re: Thanks for the help---- went with Certified Pre-Owned [pathtomax] by ateixeira

Jun 07, 2011 (8:21 am)

Replying to: pathtomax (Jun 06, 2011 7:07 pm)
Congrats on the upgrade. The H6 hasn't had the head gasket issues so hopefully it'll last longer and prove reliable for you.

Messages Page 1915 of 1929

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