brus brother Posted June 6, 2011 Share Posted June 6, 2011 (edited) I recently complained to a sube tech of P0420 code that after reset, comes back every 1100 miles or so for faulty bank 1 cat on my 05 Outback with 108K miles and was told that there was a new flash that allows for wider parameters before throwing codes. Tech wasn't sure which vehicles fit the bill but would give it a go next time I was in. He explained that here in the NE the gas is adulterated with so much ethanol and additives (apple sauce for all I know) that this seems to create a problem. I'm all for lowering the bar if it saves me from dumping $1200 for a new OEM cat that may not even solve the problem in the long run. Anyone else hear of this flash? Edited June 8, 2011 by brus brother Quote Link to comment Share on other sites More sharing options...
bheinen74 Posted June 7, 2011 Share Posted June 7, 2011 (edited) ethanol sucks. My 2 cents coming from a state where it is mandated and pushed like hot cakes on a early morning. Yes, Ethanol in the gas creates more pollution. yes ethanol yields up to 10% worse mpg. Takes more ethanol than gas to go the same distance. Ethanol ruins small engines. Ethanol requires 5 galons of water to make 1 gallon of gas (those 5 gallons are water are coming from the aluetian aquifer, MY drinking water s depleted on this) Refuse the ethanol at the pumps guys. Ethanol made from corn is causing food corn prices to go up as more farmers are subsidized to plant corn to go to ethanol. It is taking corn supply from the plate and making it go to gas. People need to know the facts. Back to on topic, sounds right, ethanol is polluting more out the pipe. It may require a ECU recurve to allow for more pollutants to pass its systems. Using this ethanol will in fact decrease usable lifespan in ALL engines. NO TO ETHANOL PLEASE Edited June 7, 2011 by bheinen74 Quote Link to comment Share on other sites More sharing options...
bstone Posted June 7, 2011 Share Posted June 7, 2011 Quit knocking the ethanol! LOL! Quote Link to comment Share on other sites More sharing options...
9098 Posted June 7, 2011 Share Posted June 7, 2011 I have the same problem with my '05 Leg (51k). When I'm in Northern Minnesota I buy the 91 octane non-ethanol gas. It's the only place I can find it. I keep a 96 olds 88 at my place out there. When I made the switch the car went from 27 mpg to 35mgg (no lie) on the highway. The locals say that is common in the gm 3.8 engine. 4 bangers do not show as big of an improvement though. However, I suspect ethanol plays a part in the HG issues of the 2.5. Ethanol will be the death of this country in more ways than one. Quote Link to comment Share on other sites More sharing options...
renob123 Posted June 7, 2011 Share Posted June 7, 2011 Yeah, I'd much rather give money to people who support terrorist groups than American farmers:rolleyes: OP: It's hard to give advice when you don't mention which car you have, but you should search for "CEL fix" here and on NASIOC. Also, a decent open source tuner in your area should be able to clear that code forever. Jacob Quote Link to comment Share on other sites More sharing options...
9098 Posted June 7, 2011 Share Posted June 7, 2011 Yeah, I'd much rather give money to people who support terrorist groups than American farmers:rolleyes: Jacob Yeah....That fuel comes from Canada. What was I thinking?! Quote Link to comment Share on other sites More sharing options...
bstone Posted June 7, 2011 Share Posted June 7, 2011 No more politics, people! Can we talk about the flash? Quote Link to comment Share on other sites More sharing options...
9098 Posted June 7, 2011 Share Posted June 7, 2011 No more politics, people! Can we talk about the flash? Fair enough. I had the ecu flashed last year & it threw the code a month later. The dealer said that the flash is the most up to date one & said the cat would need to be replaced. Quote Link to comment Share on other sites More sharing options...
brus brother Posted June 8, 2011 Author Share Posted June 8, 2011 Yeah, I'd much rather give money to people who support terrorist groups than American farmers:rolleyes: OP: It's hard to give advice when you don't mention which car you have, but you should search for "CEL fix" here and on NASIOC. Also, a decent open source tuner in your area should be able to clear that code forever. Jacob Updated original post to include "Outback" I have tried the cel fixes (spark plug anti-fouler cheaters 1 then 2 piggybacked) http://www.ultimatesubaru.org/forum/showthread.php?t=121762&highlight=p0420 post #3 partially quoted below states my experience especially involving the 05 model exception to the rule: "My recent experience with P0420 was with my 05 Outback follows. At 104,000 miles I got CEL. Autozone checked (for free) P0420 with the description you note. They erased the code as well. Car ran like crap as soon as I restarted it but smoothed out once the computer re-learned the engine. CEL came back again at about 60 miles but before I drove back to Autozone and having researched the code on-line I feared the worst that the passenger side catalytic converter was dead. I bought a cheap code reader on-line for about $20. OK now that I didn't have to drive to Autozone every time it threw a code I could experiment and with the help of the web I tried various "cheats". There is a spark plug anti-fouler ($5 for a pair at Autozone in the self help area part# 42009) that can be drilled out and used to back the 02 sensor out of the cat and fool the computer into thinking the catalytic converter is working at it's desired efficiency. I tried one then two piggybacked but my code came back (and even got a different code... ) so after a while I gave up and removed all of the cheaters and then no CEL until last week at 1085 miles later. Is your car well tuned? Have you started using cheapo gas? The dealer implied there would be a different code for O2 sensor but John's O2 suggestion is tempting my wallet's sensibility. I cleared the code again but I am prepared to get an aftermarket cat with a 5 year warranty for a third of the price of an OEM cat with a 12 month warranty. Note that my 05 Outback has a particularly expensive design in that there are 3 catalytic converters and 5 O2 sensors! This particular setup appears to NOT work well with the cheaters. I performed the modifications on the O2 sensor immediately behind the first cat on the passenger side. When I was tinkering around with the cheaters, I got yet a different code. People swear by the fix and a wink from Autozone sales seems to indicate it's common knowledge. NOTE: I have read that this friggin' code can return even after you change the cat so while I am certainly in favor of clean environment, the difference between readings that are AOK and operating just "below threshold" is a gray area for you and your wallet to mull over." I'm open to other suggestions. Is there anyone on the board with an 05 in a non-ethanol state that is getting this pesky P0420? Quote Link to comment Share on other sites More sharing options...
eulogious Posted June 8, 2011 Share Posted June 8, 2011 OP: It's hard to give advice when you don't mention which car you have, but you should search for "CEL fix" here and on NASIOC. Also, a decent open source tuner in your area should be able to clear that code forever. Jacob From the sounds of it, what Jacob is saying is that a good open source tuner should be able to find the value in the ECU ROM code, change it to something to cause the code never to come back, and then flash that new ROM code onto your ECU solving the problem. Judging from your first post and all the other info in here, the ECU is flashable, so getting the ROM, disassembling it, and correcting the issue should be possible. Especially if the ECU is already flashable, that's half the battle. Granted I have not looked at this what so ever, but I am running custom TCU firmware myself, so I do know that it is possible to do in one shape or another. Whether anyone has done it successfully is another issue. Has anyone looked into getting a custom ECU flash done by a "tuning" shop? That's where I would go. Fix the problem at it's source, the ecu. Might cost a couple of hundred bucks, but better than new cats from the sounds of it. From the sounds of it, nothing is actually wrong with the car, just the ECU saying that something is bad, and it sounds like Subaru is trying to fix the problem without saying there is a problem by fixing the problem in the ECU whenever it's mentioned, rather than the actual mechanics of the car. Sounds like some crappy firmware programming on subaru's part to me, not a bad mechanical design. Just my .2 cents. Quote Link to comment Share on other sites More sharing options...
renob123 Posted June 8, 2011 Share Posted June 8, 2011 Keep in mind that a lot of people try what they read, and usually only the people who have problems come back and complain. For how cheap it is, you should probably try it, unless you know for sure it won't work. I wonder if you have to non-foul all of the O2 sensors on your model. The ECU may be comparing values and finding that one sensor is reading way off considering the readings of the other 4. That's just speculation, though. If you can open-source tune the '05 ECU, then you should be able to make the ECU never throw/care about that code. If your emissions are like ours in Oregon, all they want to see is no codes, so this trick gets you by. Check with williaty on NABISCO. He has an '05, and he tunes. He may have another idea, but you should definitely see if he can tune that CEL out of your ECU. Jacob Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted June 8, 2011 Share Posted June 8, 2011 The non-fouler trick WILL work. The only time it doesn't work is if you have bad sensors or major exhaust leaks. Anything new enought to be flashed can have the code "tuned" out as Jacob sugests above - this is a good alternative but in most cases costs more than the non-fouler unless you can flash the ECU yourself. GD Quote Link to comment Share on other sites More sharing options...
RAYJAY Posted July 11, 2011 Share Posted July 11, 2011 Updated original post to include "Outback"I have tried the cel fixes (spark plug anti-fouler cheaters 1 then 2 piggybacked) http://www.ultimatesubaru.org/forum/showthread.php?t=121762&highlight=p0420 post #3 partially quoted below states my experience especially involving the 05 model exception to the rule: "My recent experience with P0420 was with my 05 Outback follows. At 104,000 miles I got CEL. Autozone checked (for free) P0420 with the description you note. They erased the code as well. Car ran like crap as soon as I restarted it but smoothed out once the computer re-learned the engine. CEL came back again at about 60 miles but before I drove back to Autozone and having researched the code on-line I feared the worst that the passenger side catalytic converter was dead. I bought a cheap code reader on-line for about $20. OK now that I didn't have to drive to Autozone every time it threw a code I could experiment and with the help of the web I tried various "cheats". There is a spark plug anti-fouler ($5 for a pair at Autozone in the self help area part# 42009) that can be drilled out and used to back the 02 sensor out of the cat and fool the computer into thinking the catalytic converter is working at it's desired efficiency. I tried one then two piggybacked but my code came back (and even got a different code... ) so after a while I gave up and removed all of the cheaters and then no CEL until last week at 1085 miles later. Is your car well tuned? Have you started using cheapo gas? The dealer implied there would be a different code for O2 sensor but John's O2 suggestion is tempting my wallet's sensibility. I cleared the code again but I am prepared to get an aftermarket cat with a 5 year warranty for a third of the price of an OEM cat with a 12 month warranty. Note that my 05 Outback has a particularly expensive design in that there are 3 catalytic converters and 5 O2 sensors! This particular setup appears to NOT work well with the cheaters. I performed the modifications on the O2 sensor immediately behind the first cat on the passenger side. When I was tinkering around with the cheaters, I got yet a different code. People swear by the fix and a wink from Autozone sales seems to indicate it's common knowledge. NOTE: I have read that this friggin' code can return even after you change the cat so while I am certainly in favor of clean environment, the difference between readings that are AOK and operating just "below threshold" is a gray area for you and your wallet to mull over." I'm open to other suggestions. Is there anyone on the board with an 05 in a non-ethanol state that is getting this pesky P0420? did the mod on mine over 40,000 miles ( 2004 with the 5 sensors in it ) ago it does work you have to do both sensors after the cats ..... the only problem i have had is the anti-fouler will rot off after a while ...the driver side just rusted and broke tonight Jeff Quote Link to comment Share on other sites More sharing options...
brus brother Posted July 11, 2011 Author Share Posted July 11, 2011 Jeff, You said to do Both sensors behind the cat. There are two before (upstream) two behind (downstream) the front cats and the fifth one on the rear cat. Are you saying you did the two downstream sensors but NOT the one on the rear cat? It's been about 2000 miles since I last cleared the code. (probably throw one tomorrow) Quote Link to comment Share on other sites More sharing options...
RAYJAY Posted July 11, 2011 Share Posted July 11, 2011 Jeff,You said to do Both sensors behind the cat. There are two before (upstream) two behind (downstream) the front cats and the fifth one on the rear cat. Are you saying you did the two downstream sensors but NOT the one on the rear cat? It's been about 2000 miles since I last cleared the code. (probably throw one tomorrow) on the 5th sensor i don't even know what code that one would give ????? would not be a bank 1 or bank 2 420 code that sensor covers both streams Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted July 11, 2011 Share Posted July 11, 2011 You need to put non-foulers on all sensors that are after a cat. And it looks like you need new sensors. After 100k they should likely be replaced anyhow. Change the front sensors first then if the code still returns change the rears also. GD Quote Link to comment Share on other sites More sharing options...
eppoh Posted July 11, 2011 Share Posted July 11, 2011 ethanol sucks. My 2 cents coming from a state where it is mandated and pushed like hot cakes on a early morning. Yes, Ethanol in the gas creates more pollution. yes ethanol yields up to 10% worse mpg. Takes more ethanol than gas to go the same distance. Ethanol ruins small engines. Ethanol requires 5 galons of water to make 1 gallon of gas (those 5 gallons are water are coming from the aluetian aquifer, MY drinking water s depleted on this) Refuse the ethanol at the pumps guys. Ethanol made from corn is causing food corn prices to go up as more farmers are subsidized to plant corn to go to ethanol. It is taking corn supply from the plate and making it go to gas. People need to know the facts. Back to on topic, sounds right, ethanol is polluting more out the pipe. It may require a ECU recurve to allow for more pollutants to pass its systems. Using this ethanol will in fact decrease usable lifespan in ALL engines. NO TO ETHANOL PLEASE +1 Great Monsanto subsidy Quote Link to comment Share on other sites More sharing options...
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