AKwhitetrash907 Posted July 14, 2011 Share Posted July 14, 2011 have a 96 legacy outback the cel was on for a while with just the p0420 code for the catylyst system/ o2 sensors and was running and driving fine. today drove about 20 miles turned it off for about 25min got back in turned it on. it fired up fine like normal put it in drive made it maybe 5 feet then it died. it restarted but as soon as i pushed the go pedal while still in park it died and wouldnt start again. towed it home scanned it again and now it has p0420 and p0400. anyone have a similar problem and figured it out or just know what to do? dont want to take it to the stealership if i dont have to. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted July 14, 2011 Share Posted July 14, 2011 P0400 is an EGR code. EGR valve may have failed. They usually don't cause any major issues but they can stick, get dirty, get clogged. You can try cleaning it out. You may need a new gasket for it if you remove it. I once had the small, quarter sized diameter filter on the passengers side cause EGR code and very poor shifting. It's inline with one of the vacuum hoses from the fender well to the engine and is black with a white-ish kind of material around it - though it might all be black with dirt now. Can't imagine that causing a no-start but it made mine difficult to climb a steep grade by my house. Quote Link to comment Share on other sites More sharing options...
bstone Posted July 14, 2011 Share Posted July 14, 2011 I had a no-start condition the other day when I reassembled the EGR valve the wrong way. I put the bracket behind the valve, which caused a huge vacuum leak and no-start. It might be possible that a stuck closed EGR would cause no-start. Quote Link to comment Share on other sites More sharing options...
AKwhitetrash907 Posted July 14, 2011 Author Share Posted July 14, 2011 took the egr valve off to inspect it. was semi clean and was able to suck on the hose and make it open with my mouth so fairly sure it is functioning properly. will check the little inline filter after work today. Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted July 14, 2011 Share Posted July 14, 2011 I had a no-start condition the other day when I reassembled the EGR valve the wrong way. I put the bracket behind the valve, which caused a huge vacuum leak and no-start. It might be possible that a stuck closed EGR would cause no-start. Other way around. A stuck open EGR valve will cause a massive vacuum leak and will suck excessive amount of exhaust into the engine creating poor or no combustion. I don't think 98 has a MAF sensor but if it does check the tube between the sensor and the throttle body. Make sure it is tightly clamped at each end. And none of the breather hoses or idle control motor hose (if it has it) have fallen off. Quote Link to comment Share on other sites More sharing options...
AKwhitetrash907 Posted July 15, 2011 Author Share Posted July 15, 2011 checked all the hoses and pipes no leaks or clogs. checked the inline filter air flows freely. talked to the owner of the local subaru repair shop and he said he has had a few other O.B.'s with this same problem. he said the p0400 came up as a ghost code for the fuel pump going out. tested the pump by removing the inlet line off the filter and turning the car over no fuel. going to r&r the fuel pump tomorrow after work. hopefully it will be the problem. will post up results afterwards Quote Link to comment Share on other sites More sharing options...
BigMattyD Posted July 15, 2011 Share Posted July 15, 2011 I think when you replace the fuel pump and reset the codes, it may solve your O2 sensor code as well. If the fuel pump has been running poorly for a while, it may have caused the engine to run lean enough that the ECU could not properly adjust the mixture, which might cause it to say that the o2 sensors weren't working properly, when really it is because the fuel/air ratio could not possibly be adjusted correctly. I had an O2 sensor code on my car that started happening several months before the fuel pump finally failed completely. O2 sensor was fine. New fuel pump, and no o2 codes ever since. Matt Quote Link to comment Share on other sites More sharing options...
AKwhitetrash907 Posted July 15, 2011 Author Share Posted July 15, 2011 (edited) that would make sense. the cel has been on since i got it in feb. and it wasnt getting anywhere near the mpg i assumed it should. somewhere around 15-18mpg depending on how heavy my foot was. i reset the p0420 code about a month ago. it stayed off for about 1 week and a half and about 800miles before it popped again Edited July 15, 2011 by AKwhitetrash907 Quote Link to comment Share on other sites More sharing options...
1-3-2-4 Posted July 15, 2011 Share Posted July 15, 2011 Other way around. A stuck open EGR valve will cause a massive vacuum leak and will suck excessive amount of exhaust into the engine creating poor or no combustion. This happened to me on a 98 Forester I went to check the EGR and it must of been getting stuck.. it was a pure pain to start.. It would take almost 10 seconds cranking before it had enough to start up. Quote Link to comment Share on other sites More sharing options...
AKwhitetrash907 Posted July 16, 2011 Author Share Posted July 16, 2011 I think when you replace the fuel pump and reset the codes, it may solve your O2 sensor code as well. If the fuel pump has been running poorly for a while, it may have caused the engine to run lean enough that the ECU could not properly adjust the mixture, which might cause it to say that the o2 sensors weren't working properly, when really it is because the fuel/air ratio could not possibly be adjusted correctly. I had an O2 sensor code on my car that started happening several months before the fuel pump finally failed completely. O2 sensor was fine. New fuel pump, and no o2 codes ever since. Matt yup it was the fuel pump. changed it and everything is good so far. for anyone who hasnt changed the fuel pump on a 96 legacy O.B. the acess panel is located on the passenger side behind the rear seat under the carpet and little piece of particle board. no need to try and drop the tank and maybe wiggle it to one side or the other. waste of time and effort Quote Link to comment Share on other sites More sharing options...
phxmotorelectri Posted July 17, 2011 Share Posted July 17, 2011 If we all just changed the darned things at 150k none of this would hapen... to any of us. I've had one fp last 198k. All the others failed (with varying symptoms)(all misleading and confusing) anywhere from 140k (in a big Lexus of all things) to 198 and anywhere in between. I've had at least 8 or ten cars who's fps have failed. None were instantly identified as the fp. By not replacing the fp before it's known universal failure pont causes, no assures much wasted time when such a waste could have been totally averted. By replacing the fp at 150k miles - whether it needs it or not - avoids unneeded repairs - and costly downtime. If this failure is so common (and 100% of all fps will fail before 200k mi) then why is it not a routine maintenence item? Timing belts, oil seals, water pumps are all replaced at 105k, because there is a 100% failure in at least one of these items by 125k mi. It is manditory to do this repair to maintain a warentee, and because this is when these components fail. Machinery can only last so long. Because there is a near 100% failure rate of at least one of these items (all of which must be replaced at the same time because of how the engine must be disassembled for repair). If this is an expected routine and normal maintanence proceedure, then why isn't a (simpler and cheaper) fuel-pump replacement seen as "routine maintanence. Why is it seen as an emergency (and much more costly) repair? Instead of a less costly routine maint item at 150k? A fuel pump and fp relay and filter at 150 k mi should be about $250- 300 max. It should become a normally accepted, run of the mill repair. Think of all the unneeded repairs that would never happen. So many costly and unneeded repairs. Cars reaching higher mileages before people start having to need repairs. A simple fuel pump replacement before it actually fails. Why is this not the case now? This whole thread is case-in-point... QED.... etc, etc, etc... Does any reader know how the following sentence can get more widespread exposure somehow on this website? :: "USMB does hereby encourage all members and readers to replace their fuel pumps at 150k mi in order to avart and avoid unneeded repairs and numerous mis-diagnosis. USMB believes it is in the best interest of it's members and readers to 100% avoid many unneeded troubles. When a simple solution is proven effective, the USMB encourages it's adoption. We feel that changing a fuel pump at 150k, even if is not failing, is a wise move on the part of the vehicle's owner." Quote Link to comment Share on other sites More sharing options...
AKwhitetrash907 Posted July 17, 2011 Author Share Posted July 17, 2011 If this failure is so common (and 100% of all fps will fail before 200k mi) then "USMB does hereby encourage all members and readers to replace their fuel pumps at 150k mi in order to avart and avoid unneeded repairs and numerous mis-diagnosis. USMB believes it is in the best interest of it's members and readers to 100% avoid many unneeded troubles. When a simple solution is proven effective, the USMB encourages it's adoption. We feel that changing a fuel pump at 150k, even if is not failing, is a wise move on the part of the vehicle's owner." my legacy had 212,236 miles when the fuel pump died. bought it from the original owners at 204,204 miles who had never replaced anything on it other than a head gasket at 200,000, and oil and air filters. put almost 90 miles on it yesterday and has been running great. starting to replace parts at 150,000 would be ideal for any vehicle. Quote Link to comment Share on other sites More sharing options...
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