mwd Posted December 3, 2015 Share Posted December 3, 2015 2000 OB, 132,000 miles. Local shop says codes indicate the cat is shot and the O2 sensors are out of range. Estimates total bill to be $2,300 because the car is California compliant and it needs a California catalytic converter. Is there anything to try other than replace all these parts? Quote Link to comment Share on other sites More sharing options...
mikaleda Posted December 3, 2015 Share Posted December 3, 2015 Find another shop, the cats on these subies rarley fail. 1 Quote Link to comment Share on other sites More sharing options...
Rooster2 Posted December 3, 2015 Share Posted December 3, 2015 Price is way too high. Check with auto parts companies on line for cost estimate. That being said, I agree with statement above that cats on Subies rarely fail. Quote Link to comment Share on other sites More sharing options...
ocei77 Posted December 3, 2015 Share Posted December 3, 2015 ^++++ Agree with all said. Is it a P0420 code? If so, it's generally the rear O2 sensor. Do search under the code and you'll see available options. O. Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted December 3, 2015 Share Posted December 3, 2015 If O2 sensors are malfunctioning the Cats wont function right because the fuel/air mixture will be wrong. when was the last time it had a tune-up? Spark plugs, wires, air and fuel filters, PCV valve? Any vacuum leaks or exhuast leaks can also cause the P0420 code. Was the Timing belt serviced at 105k miles? 2 Quote Link to comment Share on other sites More sharing options...
mwd Posted December 3, 2015 Author Share Posted December 3, 2015 Spark plugs - 14K ago Air/fuel filters - 500 miles ago PCV valve - never?? Timing belt done at 105K I will replace the PCV, check wires for resistance readings, buy a scan tool, check for vacuum/exhaust leaks and probably try replacing the rear O2 sensor. THANKS for the assistance!! Mike Quote Link to comment Share on other sites More sharing options...
matt167 Posted December 3, 2015 Share Posted December 3, 2015 check the rear 02 voltage with a scan tool first, make sure it's reading correctly.. If not, it might be the issue.. I found AM Auto parts has dirt cheap downstream sensors that fit these cars. I bought one for my Forester and it was $19 with free shipping, one for your car is $23... The sensor I bought works just fine. don't recommend cheeping out on an upstream sensor since it effects the fuel mapping but, a rear/ downstream sensor on a pre 2005 is just fine as long as it functions correctly Quote Link to comment Share on other sites More sharing options...
wirelessenabled Posted December 4, 2015 Share Posted December 4, 2015 If it is a P0420 code I have had that for 100K+ miles on my two 2000 OBWs. I have replaced upstream and downstream O2 sensors, checked for leaks in intake and exhaust, tune up stuff etc, etc. The code comes and goes and like I said has for over 100,000 miles on both of these cars. My suggestion is to get an OBDII sender and use Torque or some free App on your phone to read it. The bluetooth senders cost all of about $6 to $20 or so. When the P0420 code comes reset it and keep track of how long the check engine light stays out. What I found is that the CEL for P0420 takes many cycles of the car to reset itself so you really don't know how often it is being actually set without having the ability to reset it. I find that that P0420 code is set when we get a big change of weather. Like now over the last few weeks P0420 has been set 3 times about once each week. Always when the car is cold in the morning and I am decelerating from 50mph or so. After winter sets in I won't see another P0420 code for several months. In the Spring I will see it again for a few weeks. I believe the real problem is a fault in the ECU programming being too sensitive to short duration changes in what the downstream O2 sensor detects. I am still running the original cat on both of these cars. If you need to pass emissions like I do just take your code reader with you. If the CEL happens to come on while going for the emissions check you can just reset it. These cars are too old to have the OBD stuff that keeps track of how long it has been since a code was reset. $2600? Not a chance!! Forgot to add that I still get 25-27 mpg with these cars with over 200K miles on them. That is as good as I ever got even when new so I believe the car is running fine and efficiently and not polluting the environment. Quote Link to comment Share on other sites More sharing options...
nipper Posted December 4, 2015 Share Posted December 4, 2015 Just replace the wires with quality ones, as Resistance wont tell you anything about the insulation. Start with the front O2 sensor as your due. Get the codes rear properly at a (this sounds silly) autoparts store or get yourself a decent cheap one off amazon. Either way dont even let this shop clean your windows. 2 Quote Link to comment Share on other sites More sharing options...
mwd Posted December 4, 2015 Author Share Posted December 4, 2015 To wireless enabled: Both times the CEL came on was when I came down from 10,600 ft ASL to lower elevation - Wolf Creek Pass in Colorado. Both times were in the past 3 weeks. Thanks to all for the advise. I will proceed to get a code reader/app and start with the wires and vacuum hose inspection. Quote Link to comment Share on other sites More sharing options...
Rooster2 Posted December 4, 2015 Share Posted December 4, 2015 buy the 02 sensors that were made for your car. Avoid the "Universal" type 02 sensor, where you splice on your connector to the wiring. That never works out well. 1 Quote Link to comment Share on other sites More sharing options...
Natedoc808 Posted December 5, 2015 Share Posted December 5, 2015 (edited) WAIT a second, Do you live in CA?! If you do then you need a CA compliant Catalytic converter because it is stamped with a specific govt agency (CARB) number that they check for. If you do not live in CA then buy and bolt on a 49 state legal catalytic converter as functionally they are exactly the same, they are even exactly the same on the outside minus the huge fee the companies pay to have it stamped by Commiefornia. Next if you need to, get a couple O2 sensors from the local store for about 200$ total. clear the codes and go pass the smog check. If you are planning on working on any OBD2 car get a reader of some sort as it will make your life much easier. If you're in CA like me then we are F-ed!!! Edited December 5, 2015 by Natedoc808 Quote Link to comment Share on other sites More sharing options...
mwd Posted January 16, 2016 Author Share Posted January 16, 2016 Replaced wires and PCV. Checked for vacuum and exhaust leaks - none found. Bought scan tool and OBD Fusion app. Test drive today with scan tool. Bank 1,Sensor 1 wide range voltage varied from 3.7 to 4.4 volts. Bank 1, Sensor 2 voltage varied mostly inversely with Sensor 1 between near zero to 0.9. Long term fuel trim sometimes straight lined at -2.4%. Short term fuel trim varied from +2% down to -18%. On the "Dashboard" there was a O2 Sensor 1 that came setup with the software that read zero all the time. My newbie guess is that the front O2 sensor should be replaced first. Then watch the readings and see how the rear sensor reacts and replace as necessary. We live on the western slope of Colorado - no emissions checks. Mike Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted January 16, 2016 Share Posted January 16, 2016 3.7 is kinda lean. 4.4 is VERY lean. Was it hitting 4.4 only when you were decelerating? If it has a MAF sensor, check your MAF flow rate at warm idle, and at 2500 rpm in park. If it has a MAP sensor, I've heard of those going bad and causing problems. You could have an exhaust leak at the head flange causing that. Those are hard to hear and impossible to reach around and feel for. I like to use a long section of 3/8" ID fuel hose. Stick one end to your ear and fish the other end all around the exhaust flanges. If there's a leak you'll hear it. Quote Link to comment Share on other sites More sharing options...
AdventureSubaru Posted January 16, 2016 Share Posted January 16, 2016 Ignore the post about replacing cats with CA compliant ones. That's only ever necessary when cats are replaced, which yours very likely do not. It will be something else. Only cats I've ever seen fail on a subaru were at 365,000 miles Quote Link to comment Share on other sites More sharing options...
mwd Posted January 17, 2016 Author Share Posted January 17, 2016 Checked for leak at exhaust flanges at idle and higher RPM (~1500 RPM). None found using hose to ear technique. New gaskets at heads recently with head gasket replacement. Car has MAP sensor: Warm idle = 6.5 inHg. 2500 RPM = 5.9 inHg. Drove car again logging Upstream O2 and post cat O2. Saw 4.7 V upstream O2 during decel. As low as 3.2 at WOT, 5th gear uphill 2500 RPM. Here are some screen shots of Upstream O2 =GREEN range 0-5 volts. Downstream O2 = RED range 0 - 0.9 volts. These O2 sensors have never been replaced as far as I know. 2000 Outback Limited 5 sp. 2.5L. Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted January 17, 2016 Share Posted January 17, 2016 No air/vacuum leaks, no exhaust leaks, I think I would change the front sensor. Especially if its original. Front sensor is reading lean and the rear sensor is reading slightly rich. Kinda looks like the ECU is trying to compensate for the lean reading by adding a bit more fuel, but not enough to throw the fuel trims way off. Quote Link to comment Share on other sites More sharing options...
mwd Posted January 17, 2016 Author Share Posted January 17, 2016 The scan tool app thinks the front sensor is a wide range type. It does not cycle up and down much compared with what I have read re: front O2 sensors. Do wide range sensors not cycle rapidly? Or maybe the scan tool app does not respond to the fast cycling? Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted January 17, 2016 Share Posted January 17, 2016 It is a wide range. If it were a standard O2 sensor the voltage range would be 0 -1.0 volts. No, wide band sensors don't vary quickly like narrow band sensors do. The catalysts used on the cars with wide band sensors work differently, and don't need the rich-lean swing that is necessary for a typical 48 state cat to work. Quote Link to comment Share on other sites More sharing options...
mwd Posted January 17, 2016 Author Share Posted January 17, 2016 Thanks for all the help. I'm with the sheep, too. I'll get a new OEM front O2 sensor ordered. Quote Link to comment Share on other sites More sharing options...
AdventureSubaru Posted January 17, 2016 Share Posted January 17, 2016 Sounds like a good plan. At that age/mileage, they'd have limited life left anyway. Quote Link to comment Share on other sites More sharing options...
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