Our family has 3 Subarus. On our 2009 Impreza 2.5i I was getting the p0420 code. We drove it that way for several months not knowing if it was the Catalytic Converter or one of the o2 sensors. I called the local Subaru dealership and they said I would have to pay for a diagnostic and a replacement Catalytic Converter if that was the problem.How To Address a Subaru P0420 (Step by Step) NSUGS. 162 subscribers. Subscribed. 260. 16K views 1 year ago. The nerdy and keen eyed will notice I omitted …J. Jdave Discussion starter. 7 posts · Joined 2017. #11 · Sep 11, 2019. A code P0420 may mean that one or more of the following has happened: Leaded fuel was used where unleaded was called for (unlikely) A damaged or failed oxygen / O2 sensor Downstream oxygen sensor (HO2S) wiring damaged or connected improperly.P0420 definition: Catalyst system efficiency below threshold (Bank 1) Issue Severity: MODERATE - Extended driving with this code can cause internal engine damage. Repair Urgency: Get this code fixed as soon as possible to avoid further damage to your emission system and possible engine damage.Hard shifts, jerking under load, P0420 engine code after new timing belt/water pump ... I have a 2001 Subaru Forester (Auto) with 138,393 miles on it. With some help, I replaced the water pump and timing belt a few days ago. I followed all instructions for setting the timing. However, I immediately noticed that the shifts were harder ...Im getting the p0420 in an 04 forester 2.5xt turbo. Ive narrowed it down to actually being a cat problem. My issue is trying to figure out which cat to buy. ... We're the best Subaru Forester Owners Forum to talk about the best years of the Subaru Forester, modifications and reliability history of the Subaru Forester.Potential Causes of the P0420 Code. Several issues can trigger the P0420 code in your Subaru Forester: Faulty Catalytic Converter: The most common cause, often due to …VSurfn. 1329 posts · Joined 2014. #2 · Jul 22, 2018 (Edited) P0420 code stands for “Catalyst System Efficiency Below Threshold (Bank 1).”. When you receive a P0420 code it means your catalytic converter is not operating at maximum efficiency. Usually this means your catalytic converter needs to be replaced and/or your O2 (oxygen) sensors.For a couple of months now Ive had P0402 P0420 Come on. Often shortly after refuelling. My car has run 225000 kms by now. ... We’re the best Subaru Forester Owners Forum to talk about the best years of the Subaru Forester, modifications and reliability history of the Subaru Forester.The P0420 code can actually point to a lot of different things. In a rush to head out of town, I got an oil change at a subpar quick lube place, and got a P0420 code about 100 miles down the road. Took it over to a buddy's place when we got back into town, and he said "this cheap oil filter is probably throwing the code".2005 Forester bought last year for my son who is in school about 3 hours away. Chasing a re-occurring P0420 code, I have replaced or checked the following: PCV valve – OEM – original valve was not clogged Plugs – NKG – removed plugs looked good, no evidence of oil or unusual wear. Wires- NKG Front and Rear 02 sensors – DensoMy forester is a 2nd generation 2003 Subaru Forester and I am the second owner going on 7 years now and its has been through a lot to say the least. I have put 115,000 miles on my car. ... I now realize it has something to do with the good ol' P0420 code. This starting issue has progressed over time, but would not happen regularly, so it became ...Forester 2001 L - Stock 101k Miles P0420 - Catalytic Converter Efficiency Below Threshold The forester has been throwing this code for a few months now, typically shows up on long highway runs (but to be fair, that is the vast majority of my driving). ... We're the best Subaru Forester Owners Forum to talk about the best years of the Subaru ...Technical Forums and Vehicle Assistance. General Troubleshooting and Technical Help45844 posts · Joined 2007. #4 · Jul 22, 2014. Yes, fixing the P0420 CEL code could improve your gas mileage. The rear O2 sensor on the '03 monitors the exhaust flow for excess 02 & doesn't affect the operation of the engine as it does on the '05+. The P0420 CEL code could be caused by many things, but one is an over rich condition which ...Shortly after we bought our 2005 Impreza Outback Sport with 253K miles last summer it started throwing P0420 codes and after a reset, the code returns after 8- 10 miles. On our 2003 Forester we bought a year ago at 223k miles, it threw a P0420 earlier this year, then again about two weeks ago. I ...Oct 19, 2015 · The P0420 code can actually point to a lot of different things. In a rush to head out of town, I got an oil change at a subpar quick lube place, and got a P0420 code about 100 miles down the road. Took it over to a buddy's place when we got back into town, and he said "this cheap oil filter is probably throwing the code".I kept pulling that code as well. 2006 Forester. So I pulled the O2 sensors. Still got the code. So I pulled the front Cat. Still got the code. So I pulled the rear Cat, muffler, intermediate, put in new spark plugs, and ran a cleaner. Still got the code (although now it goes on and off every couple weeks or with temperature).So I installed the $5 mechanical fix for P0420 and now have P2096 (Post cat too lean.) I use both spacers the one connected to the O2 sensor drilled, the 2nd undrilled. ... We're the best Subaru Forester Owners Forum to talk about the best years of the Subaru Forester, modifications and reliability history of the Subaru Forester.2008 - O2 Sensor and P0420 Cat Code? ('06-'08) Jump to Latest Follow ... Subaru Forester Owners Forum. 2.6M posts 191.2K members Since 2006 We're the best Subaru Forester Owners Forum to talk about the best years of the Subaru Forester, modifications and reliability history of the Subaru Forester. ...2013 Outback P0420 code. Hello, I am new to this forum and Subarus meaning that this is my first Subaru and first post. Thanks for all the great information. I currently have a P0420 code and am trying to determine the issue. I have a 2013 Outback with 121k miles which I bought back in March 2017. There were lean codes which were due to some ...Forester 2001 L - Stock 101k Miles P0420 - Catalytic Converter Efficiency Below Threshold The forester has been throwing this code for a few months now, typically shows up on long highway runs (but to be fair, that is the vast majority of my driving). I bought a scanner from scantool.net...It only takes a pinhole in the exhaust, near the rear O2 sensor to trigger the P0420 CEL code. The only function for that O2 sensor in your '01 is to monitor the efficiency of the CAT... to check for excess O2 in the exhaust flow. If your gas mileage & engine performance is normal, then I'd look for holes in the exhaust.2.5x_sleeper. 45860 posts · Joined 2007. #5 · Dec 26, 2009. My guess is a failing front O2 sensor, causing an over rich condition. This would give you the gas smell & would overwhelm the CAT. The rear O2 sensor, which monitors the CAT, would give you the P0420 CEL code. Sounds like what happen in my '03. :wink:I'm looking for some insight on a constant p0420 that I can't get rid of. I've replaced the catalytic converter and both sensors, I don't have any exhaust leaks anymore that I can hear and I've tried installed the $5 "fix" to see if I could get it to go off so I can pass the car. ... We're the best Subaru Forester Owners Forum ...Any brand of motor oil is suitable for a Subaru as long as the viscosity is correct. Some Subaru models require synthetic oil. The type of oil also may depend on the year of the ca...Diagnostic trouble code(DTC) P0420 stands for “P0420 Catalyst System Efficiency Below Threshold (Bank 1).”. It indicates that the exhaust system’s oxygen levels are below the required threshold in Bank 1, which can damage the engine’s exhaust and fuel system. Bank 1 refers to the side of the engine that houses the number one cylinder.Subaru 2007 Forester, now 138k miles. Above condition began intermittently Novemeber 2014. No obvious driving performance issues. In September 2014 had major maintenance performed by Subaru dealer. ... As for the P0420, you could remove the catalytic converter and clean it with citrus cleaner. There are numerous threads on this, but basically ...Walk with the very creative advocates for the US Forest Service and the Appalachian Trail on this legal journey through the land. It’s not every Supreme Court brief that goes off t...So heres my issue, I have a 2004 Subaru forester X with around 138k miles on it, couple months ago my engine went out so I swapped a rebuilt ej25. Engine runs fine but its idles fairly high at time around 1k-2k rpms. Originally I got a code for the rear o2 sensor. Replaced it but problem persisted and I started getting a p0420 code.He has many many used foresters for sale and probably has a rebuilt engine ready to go or he can do yours. He is comparably cheap. Ph-717-426-4142. Tell him Al Conrad sent you. The other guy is every bit as good but a bit more expensive and probably doesn't have a rebuilt. He is Subaguru 717-786-2304.Oct 19, 2015 · The P0420 code can actually point to a lot of different things. In a rush to head out of town, I got an oil change at a subpar quick lube place, and got a P0420 code about 100 miles down the road. Took it over to a buddy's place when we got back into town, and he said "this cheap oil filter is probably throwing the code".Feb 20, 2015 · The P0420 code is for low cat efficiency. It is unrelated to the cruise control, although the cruise light will blink (and the cruise control is disabled) on any CEL. I would say it was simply an odd coincidence (unless your car is possessed by an evil spirit). KianLM said: I also developed a head gasket leak.Reliable 2010 Subaru Forester - $4,300 Looking for a trusty companion to conquer any road or weather condition? Look no further than this 2010 Subaru Forester! ... - Check Engine Light (Code P0420): Catalyst System Efficiency Below Threshold. May affect emissions and fuel efficiency, but not safety. Catalytic Converter ~$1K replacement.Cats do fail on a regular basis, odd fuel trim/missfire problems destroy the cat, or pinhole exhaust leaks set off the P0420 code. Not so much on Subarus. I see a lot of subaru cat's replaced because of the P0420 code, often with inferior aftermarket cats, and 10 months later the light is back on and the customer is out $600 or more.Dec 2, 2021 · Forester 2001 L - Stock 101k Miles P0420 - Catalytic Converter Efficiency Below Threshold The forester has been throwing this code for a few months now, typically shows up on long highway runs (but to be fair, that is the vast majority of my driving). I bought a scanner from scantool.net... www.subaruforester.org.P0420 Subaru: Code Meaning, Causes, Symptoms, & Tech Notes The Engine Control Module (ECM) monitors the switching frequency ratio of heated oxygen sensors 1 (front O2 sensor) and heated oxygen sensors 2 (rear O2 ... We're the best Subaru Forester Owners Forum to talk about the best years of the Subaru Forester, modifications and reliability ...If the upstream and downstream oxygen sensors determine that one of your Forester's catalytic converters is not doing its job properly, it'll throw the trouble codes P0420, or P0430 respectively. If you have this code AND the smell of rotten eggs, it is very strong evidence that the catalytic converter is bad. DiagnosisHey guys, I recently have been having issues with my 2019 subaru. I went to go get the diagnostic code and it came out p0420. Apparently it's the catalytic converter, but I feel like it's to new of a car to have issues with it.My '11 (140k miles) has been throwing a P0420 code along with running a bit rough, it stalls from a start (oddly the autostart has no issues keeping it running), and I'd say I'm down to about 70% power overall. ... We're the best Subaru Forester Owners Forum to talk about the best years of the Subaru Forester, modifications and reliability ...I'm very new to these Forester hells having just gotten a 2010 and recently got the dreaded P0420 code. In Youtubes suggesting several possible solutions the catalytic converter cleaner added to 1/4 full fuel tank was the first suggestion. ... We're the best Subaru Forester Owners Forum to talk about the best years of the Subaru Forester ...So my wife and I bought an '07 Outback Basic back in January, used with about 130k miles on it. MIL came on around 6 weeks ago with a P0420 code. Been doing a lot of googling/reading about P0420 codes lately- I've had several conversations with different mechanics around town, some helpful and some not, but someone suggested that since the only ...The Continental ContiProContact tire is the best overall tire for the 2015 Subaru Forester as of March 2015, according to tire review site BestReviews.com. The site also recommends...youre running deact arnt you? il put money on its the p0420 code which is cat operating beyond or out of limit. i sometimes get it on mine but i just read it and clear it with the psi3. we all bought an american code reafer last year which was pretty good value for money and could be used as a digital gauge too, its in the garage somewhere il have a look!!2008 - O2 Sensor and P0420 Cat Code? ('06-'08) Jump to Latest Follow ... Subaru Forester Owners Forum. 2.6M posts 191.2K members Since 2006 We're the best Subaru Forester Owners Forum to talk about the best years of the Subaru Forester, modifications and reliability history of the Subaru Forester. ...I have a 2011 2.5x (65k miles) and the CEL light came on after filling up with gas a few weeks ago. I checked to make sure gas cap was tight and CEL was still on. I had the codes read and it showed P0171 & P0420. I reset the codes to see if it might have just been the gas cap, but CEL came back on. I've noticed a decrease in gas efficiency ...P0420 is almost always the O2 sensor. 3. Reply. Share. Zyzzyva100. • 3 yr. ago. Not sure how it works on the forester, but I had this happen to my challenger when it was about 9 years old and I just ran some catalytic convertor cleaner through and that solved the problem. But yea, most likely the O2 sensor. 1.I figure I'd give this thread a quick update. We did the catalytic converter stew with citric and oxalic acid in July of 2019, and our 2002 Forester, which previously had a nagging problem, has been P0420-free ever since. 18 months and counting... ~ Silke ~. '02 Forester S 5MT - "Cooper". '11 Honda CR-Z 6MT - "Kat".BTW, the P0420 probably won't clear itself, even if you somehow removed the 'cause'. You need a reader/eraser to do that task (or disconnect the battery for 30 minutes or so ... We’re the best Subaru Forester Owners Forum to talk about the best years of the Subaru Forester, modifications and reliability history of the Subaru Forester.Good luck repairing your Subaru Forester! P0030 is a very common OBD2 trouble code. It's generic, which means it has the same definition for the Subaru Forester as any other vehicle. This code is almost always caused by a bad heated oxygen sensor or wiring issue. P0030 Definition: Heater Control - Circuit - B1S1 P0030 indicates no signal coming ...A P0420 code means your catalytic converter is working with low efficiency. The citric acid bath may be one fix. There is also a 'mechanical fix' - search the forum. ... We're the best Subaru Forester Owners Forum to talk about the best years of the Subaru Forester, modifications and reliability history of the Subaru Forester.The P0420 CEL code comes from the rear O2 sensor which monitors the efficiency of the CAT. That means the rear O2 sensor is detecting too much O2 in the exhaust flow. ... We're the best Subaru Forester Owners Forum to talk about the best years of the Subaru Forester, modifications and reliability history of the Subaru Forester. Full Forum ...Drop the splash guard and pull the plastic tabs closest to the fender well from under the car. You're going to need a 22mm wrench to remove the sensors, and the wiring harness is hard AF to remove. You may have to pull the large metal brace down, it's just 2 12mm bolts (one front one rear) holding it up. Then you'll have full access to everything.03 Forester X 154,000 Miles. Bought in October 2020 About a month ago I got a CEL it turned out to be the P0420 code. No loss of performance. Since then I changed spark plugs and did the $ 5 fix, but still get the code when I drive on the highway. I assume both O2 are the original ones. No exhaust leaks that I can detect.The CEL went out and all seemed good. Now 300 miles later I have 2 codes, P0420 and P0031. Both are listed as confirmed and a P0420 is also listed as permanent. I reset the system to clear them. I thought after I made the repair that the permanent code would clear itself but hasn't. The car runs perfectly however.Aug 20, 2020 · Tech Notes. As the code description implies the P0420 code means that the vehicle's control module has detected that the three-way catalytic converter is not working properly (is not as efficient as the factory is expecting). Replacing the oxygen (O2) sensors may sometimes fix the code, but in most cases the catalytic convert needs to be ...Aug 24, 2017 · It only takes a pinhole in the exhaust, near the rear O2 sensor to trigger the P0420 CEL code. The only function for that O2 sensor in your '01 is to monitor the efficiency of the CAT... to check for excess O2 in the exhaust flow. If your gas mileage & engine performance is normal, then I'd look for holes in the exhaust.2002 Subaru Forester S P0420 Own a 2002 Forester S (purchased late 2001), 127,000+ miles, mostly city driving the past 6 years or so. Would like to keep the car for my teenage son, who will start driving this summer. Have always used mid-grade gas in the car, and am religious about oil changes, etc.63 posts · Joined 2011. #1 · Jan 10, 2012. I have a 2004 OBW and it keeps throwing the P0420 catalytic system below threshold code. The car is bone stock. It is drive by wire and has the California emissions on it. It's engine is a model EJ259 if I remember correct. I've tried using the anti-foulers, and even the electronic fixes in the rear ...The P0420 CEL code + reduced gas mileage would point me upstream. The rear O2 sensor is good, as it's telling you there too much O2 in the exhaust... as in, you're running too rich. So rich that the CAT can't reduce the O2 levels. That would also explain the poor gas mileage.When the pressure inside of the fuel tank is too high, P0453, is thrown and the check engine light comes on. If the only trouble code that you have is P0453, your Forester is in no risk of breaking down. The EVAP system is responsible for migrating fuel vapor. Whether it is doing that or not, has no effect on the way your engine runs.Nov 30, 2018 · The most common fix for P0420 in the Subaru Forester is a new catalytic converter, followed by an O2 sensor replacement. Before taking your Forester into an exhaust shop for an (expensive) new catalytic converter, let’s ensure that’s what you need. Here’s a good P0420 diagnostic order for the Subaru Forester: 1. Check for Other Codes.As to air exposure, that would equal a P0420 CEL code, hence the reason for the $5 fix with the end sealed Bobby.... ['07 FSXT Member Journal] ['03 X Member Journal] 2007 Forester Sports XT - COBB Surgeline dyno stock Protune - Stage 1+ 2003 Forester X +AVO turbo kit = XT (son's) ... Subaru Forester Owners Forum. 2.6M posts 191.2K members2005 outback 3.0, p0420 bank one sensor 2 New Desno O2 sensors, new cat ... Although it refers to Bank 1, where there's a separate cat for each bank Subaru uses P0420 for efficiency below threshold for either bank. There's no code for CATALYST SYSTEM EFFICIENCY BELOW THRESHOLD for Bank 2, even though this is a possibility. ...Petrochemical giant Ineos was granted a permit to cut down a wood to build a new plastic plant in Antwerp. A provincial government in Belgium on Thursday (November 7) granted Europ...Get ratings and reviews for the top 11 lawn companies in Forest Park, OH. Helping you find the best lawn companies for the job. Expert Advice On Improving Your Home All Projects Fe...HELP: Code P0420. My 2009 forester has the “cruise” light blinking and a solid traction control off and check engine light. I got the diagnostics ran and it came out with “P0420: catalyst system efficiency below threshold bank 1”. This happened to me last year but ignored the symptoms for about a month and then had to get it taken in ...Forester 2001 L - Stock 101k Miles P0420 - Catalytic Converter Efficiency Below Threshold The forester has been throwing this code for a few months now, typically shows up on long highway runs (but to be fair, that is the vast majority of my driving). I bought a scanner from scantool.net... www.subaruforester.org.189 posts · Joined 2009. #1 · Jun 15, 2015. P0301 Cylinder 1 misfire. P0302 Cylinder 2 misfire. Got it for the first time yesterday. I got both the constant illuminated CEL and the flashing "catalyst damage" CEL. I cleared the code and it hasn't come back today. From what I read, the ECU calculates crankshaft speed using the crank and cam ...2002 FS code P0420 Need Advice. Jump to Latest Follow 2K views 2 replies 3 participants last post by 05SilverXS Sep 28, 2014. R. recon6606 Discussion starter 16 posts ...CLEAN Your CAT - Fix stubborn P0420 Here's what I did: On 2005 Forester XT with P0420, 1. Removed downpipe/catalytic converters. 2. Separated into upper Cat and lower Cat. 3. In a 5-gallon bucket, mixed 4 gallons water, 10 oz. Citric acid and 7 oz Oxalic acid. (Purchased on Amazon - $20) 4. Soaked main Cat in acid overnght, rinsed completely ...