P0420 subaru forester

Written by Amug NpfpmLast edited on 2024-07-08
Subaru Mechanic: Ronnie. Normally you can replace th.

Tool Tip: Diagnosing Subaru's P0851/P0852 DTCs. The purpose of this bulletin is to assist when diagnosing DTCs P0851 (Neutral Switch Input Circuit Low) and P0852 Neutral Switch Input Circuit High). If you encounter a ­vehicle with DTC P0851 and/or DTC P0852, use the repair procedure in this Tool Tip. Models Affected: 2005-'06 Legacy ...Here's an Amazon link to that impact gun → http://www.amazon.com/gp/product/B00BWFIKZO/ref=as_li_qf_sp_asin_il_tl?ie=UTF8&camp=1789&creative=9325&creativeASI...There is a lot of info out there on this subject but none seemed to be specific to an intermittent power loss issue with P0420. I understood one sensor should fluctuate rapidly (upstream) and the other should remain fairly steady. If I recall correctly, the fluctuation was between about .04-.80.Dec 19, 2013 · And, a P0420 code really reflects the relationship between the two (front and rear) sensors - not just the rear sensor alone. Depending on your vehicle mileage, your front oxygen sensor may actually be starting to fail - they don't last forever - and the front sensor definitely does contribute to vehicle operation.2.5x_sleeper. 45859 posts · Joined 2007. #2 · May 17, 2020. @Jaime ochoa welcome to the forum from Oregon! The P0420 CEL code is from the rear O2 sensor, but that doesn't mean the sensor is bad. The rear O2 sensor is monitoring for excess 02 in the exhaust flow, so the fault could be something upstream... even a pinhole leak in the exhaust ...Nov 3, 2013 · P0420 code, running rich My car, 1999 Forester was giving me fits, running well most of the time, but it started setting the dreaded P0420 code and I noticed that it was running rich, gas mileage dropped to 17 where it usually gets 29 to 31 mpg highway. Also, the idle was wild at times, either idling at 1800, or bouncing between 500 and 1000 rpm.Fits Forester (2004 - 2005) EGR Valve Temperature Sensor A failed EGR Valve Temperature Sensor will often have no noticeable symptoms beyond a check engine light, but it does cause your Subaru Forester to operate inefficiently and produce higher emissions. Our technicians have access to manufacturer-approved repair processes and Subaru genuine ...P0420 is the front cat. It's needs to be replaced....and it'll be under warranty.. FREE. TrailAngel 2010 2.5X 5MT. Save Share. Like. J. james gais Discussion starter 13 posts ... 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 ...M. MTpuckstopper Discussion starter. 9 posts · Joined 2023. #1 · Aug 24, 2023. Vehicle Details: 2005 Forester XT. 2005 Forester XT stock except for my son added an Invidia turbo back exhaust. It looks like it is catless and has one O2 sensor. Just had shop try to address the P4020 code without success.Esta página está pensada para ayudarte a solucionar los problemas de Código de avería P0420 del Subaru Forester. Cubre el significado de Subaru Forester P0420, los síntomas, las causas y las posibles soluciones. En el Forester, el OBDII P0420 suele estar causado por un sensor de oxígeno defectuoso, pero también puede haber otras causas.B. bdubbs84 Discussion starter. 13 posts · Joined 2008. #7 · Oct 20, 2008 (Edited) Well, I got rid of the P0420 catalyst code, but now I have two new codes. One is P0440 (Evap. Emission Control System Malfunction) and the other is P0136 (O2 Sensor Circuit Malfunction, Bank 1 Sensor 2). I already have the O2 sensor spacer in place.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.WAKE FOREST, N.C., April 28, 2020 (GLOBE NEWSWIRE) -- Wake Forest Bancshares, Inc., (OTC BB: WAKE) parent company of Wake Forest Federal Savings... WAKE FOREST, N.C., April 28, 2...Sep 11, 2019 · 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.Safe to Drive with P0420 code? Long story short, I had a milltek turboback system with 100 cell cat fitted on Friday and I was out and about today and pulled out of a corner in 3rd, changed down to 2nd and put my foot down. As soon as I did that the CEL light and traction control light came on with the cruise control light on, still ran fine ect.Viewer questions on Subaru WRX and Forester engine problems are answered by a couple of long time Subaru enthusiasts and parts guys. This is the first episod...For the past six months or so on my 02 Forester L, my CEL has been going off and on. When on, it gives the P0325 and P0420 codes. I know what these represent; what I don't know is whether there might be a relationship between the two. That is, what might cause them to go on and off at the same...Subaru Forester P1604 OBD-II Diagnostic Powertrain (P) Trouble Code Information Page. Reason for Subaru Forester P1604 and find the solution for the code Subaru Forester P1604 , we'll give to how to fix Subaru Forester P1604 trouble code problem. p1604.enginetroublecode.comThere are many things that can cause the P0420 trouble code in your Forester. Here are the most common ones. Oxygen Sensor - The P0420 codes is thrown when the oxygen sensors on both sides of the exhaust have very similar readings. When the oxygen sensor is bad, it can cause a false reading and trigger the code.This Service Information Bulletin announces diagnostic service procedures to be followed when DTC P0420 (Catalyst System Eficiency Below Threshold Bank 1) is detected by the Engine Control Module (ECM). If DTC P0420 is found to be stored in the ECM, follow the diagnostic procedures outlined below.The P0420 engine code indicates the catalyst system efficiency is below the threshold (Bank 1). A P0420 code indicates a problem with the catalytic converter, more specifically. The purpose of the catalytic converter is to break down harmful pollutants created during the combustion cycle. By using fine platinum and gold meshes to filter exhaust ...And it was the same as usual, P0420 and P0442. I've had P0420 since I got the car in june 2011, but didn't bother as, according to my mechanic, "it's just because the computer doesn't recognize the aftermarket catalyst". Back then, gaz mileage was on close to manufacturer's specs (11L per 100km city = 21MPG, ~9L/100km highway = 26MPG) so I ...P0420 Subaru Catalyst System Efficiency Below Threshold Bank 1. As the code description implies the P0421 Subaru 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 ...Travel to national forests is trending for summer 2021. This is why national forests can be more fun than national parks, from being free and less crowded to having fewer rules. In...P0420. I have a 2004 Legacy 2.5 California spec (3 cats, 5 O2 sensors) with a recurring p0420 pending code on bank 1 that keeps popping up on my blue driver for the past 2000 miles. The cats were replaced under warranty about 8-9 years, 100,000 miles ago. The Oxygen sensors are all original, so they have 167,000 miles on them.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. Do any of you have successful experience with that, or terrible experience with that like it ate gaskets ...The nerdy and keen eyed will notice I omitted the valve lash adjustment on these 2008-2010 Subaru products with the 2.5L engine...because nobody and I mean N...ayarnell7. 1 post · Joined 2022. #8 · Jan 11, 2022. 2008 Impreza 2.5 - had C0071, C0075 and C0042. My nephew's car. I noticed right away some corrosion on the positive battery terminal. Cleaned and treated with corrosion preventative spray, then looked at all the engine ground connections, all looked good.Apr 10, 2011 · Hey all, new to the fourm. I have a 03 2.5 xs with about 135k. The cel fires two identical p0420 codes about once a week. I have done a visual inspection and everything seems to be in order. i have a actron super auto scanner and use it under global obdii.Dec 27, 2022 · FIXD code detected was P0442 – Evaporative emission control system leak. I had FIXD clear the code prior to taking my 2005 Subaru Forester to a mechanic. The engine light and cruise control lights went out. Today a week later, the lights are back on. I used FIXD and Code P0420 – Catalyst System Efficiency was detected.I have a 2009 Forester 150k miles that throws a P0420 code, it happened 4 times over the course of six months and has gone away after a few days until now. ... Forester Owners Forum to talk about the best years of the Subaru Forester, modifications and reliability history of the Subaru Forester. Show Less . Full Forum Listing.I have a 2012 Subaru Forester Premium X that is throwing a P0420 code. It has a little over 225000 miles. I replaced the engine that threw misfire codes due to low compression at 223000. It is a used engine off of ebay that had 49000 miles on it. I have read a lot on the P0420 code and am experiencing some different symptoms than what I have read.2009 - P0600 and P0420 - Updated! 2009 2.5 4EAT, Premium, 135000 miles. Ive been getting a P0420 for the last year. Even after a new exhaust was installed, including new sensors. Sadly, for me, I just reset the code each time it occurs as the car generally runs "OK". I drive about 70 miles each day (35 miles each way) for a commute …Subaru Forester 2014 I have a cel with code p0420 on and off,CEL came up drove for 70KMS and it went off the moment I had filled in gas. It comes on and off. Should I take it to mechanic or keep driving This thread is archived ... P0420 Code Honda Accord 2016.Paid $90 for useless test. I bought front sensor off Amazon for less than $100. Installed sensor, reset code. On the second highway trip the cel trips code 0420. I rerun subaru test procedure. Results show sensors fine, bad cat. I replace the rear sensor so that when I take the car back to Subaru they should have no option but to replace the …Stopped by autozone to see what the code was and came up P0420 catalyst efficiency below threshold bank 1. ... I am not sure if this would cover your problem but it may be worth asking a local Subaru dealer. Seagrass . SOA 1-800-782-2783, MY11 Outback 3.6R Premium (Sold Jan 2022), MY12 Forester XT 2.5 (Youngest daughter) MY07 Liberty/Legacy 2.5 ...My Forester (1999, 125,500 miles) started acting strange last night. On my way home, it felt like it was losing power, then felt like a cylinder or two were misfiring, then started sputtering and stalling. Luckily, I was able to make it home. Diagnostics told me that three of my four cylinders were misfiring, so I purchased plugs & wires ...The P0420 code will not likely be caused by, or cleared by removing and replacing, the gas cap. The gas cap could be faulty, and is causing the warning lights to come on for some other code, but it's not the P0420. Just because at one time the lights came on and code then was a P0420, doesn't mean that every time the lights come on, it's for a ...1990 to Present Legacy, Impreza, Outback, Forester, Baja, WRX&WrxSTI, SVX; All Activity; Home ; Newer Generations of Subaru discussion ; 1990 to Present Legacy, Impreza, Outback, Forester, Baja, WRX&WrxSTI, SVX ; Check engine light code P0420 Check engine light code P0420. ... The auto parts store read it as a P0420 code - catalyst, low ...ayarnell7. 1 post · Joined 2022. #8 · Jan 11, 2022. 2008 Impreza 2.5 - had C0071, C0075 and C0042. My nephew's car. I noticed right away some corrosion on the positive battery terminal. Cleaned and treated with corrosion preventative spray, then looked at all the engine ground connections, all looked good.Hi guys. New to the forums. Just bought a 2005 Forester XS N/A and I too have the dreaded P0420. Previous owner had the catalytic converter replaced before I bough the car so I didn't think it would be a bad cat. Got under the car this weekend and found an exhaust leak where the catalytic converter bolts to the y pipe.In all seriousness, the P0420 is only good for making your wallet lighter by either ~$100 for a new sensor or several times that for a new cat. I've never seen a P0420 actually point to a bad catalytic converter. As far as how an O2 sensor works, I'm not entirely sure. There are a bunch of different types using 1, 3 or 4 wires.2014 FXT FA20DIT: P0420 Catalyst system efficiency below threshold. ('14-'18) Jump to Latest FollowKażda zgłoszona szkoda czy wypadek wpływa na historię ubezpieczeniową kierowcy. Ubezpieczyciele biorą pod uwagę liczbę i rodzaj zgłoszonych szkód oraz okoliczności, w jakich doszło do wypadków. Kierowcy, którzy często zgłaszają szkody, są postrzegani jako bardziej ryzykowni, co prowadzi do wyższych składek ubezpieczeniowych ...32 posts · Joined 2015. #11 · Dec 24, 2015 (Edited) P0420 - need some specific help. From what I understand, that rear o2 sensor waveform in the third picture is classic sign of a bad cat. It's likely that waveform that is triggering the code. The others look more stable, unless the scale is off. But the rear still mirrors the front.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.Forester Code P0420& Hesitation. I have ongoing problem with my 2000 Forester 2,5 Non Turbo with 161K. I have replaced Ignition coil, Spark plugs, fuel filter, wires, ICV sensor, replaced valve cover gaskets, the car has CL with code P0420 but thing is there is no restriction in the exhaust, no soothing, no bad smell, MPG is normal. but I found ...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.The next Subaru is a 2006 Forester. This car was very tolerant of the same type of auto parts. I got this 2001 Outback last fall...if it had been my first Subaru, it would be my last. ... P0420 is a nag code with these, and sadly is not well defined or contained (I think a 2005 or newer subaru, one would get additional codes to trace it better).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 ...The P0420 is the only code and it just started. The last on the VIN are 4H748003. ... 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. Show Less . Full Forum Listing. Explore Our Forums.Paid $90 for useless test. I bought front sensor off Amazon for less than $100. Installed sensor, reset code. On the second highway trip the cel trips code 0420. I rerun subaru test procedure. Results show sensors fine, bad cat. I replace the rear sensor so that when I take the car back to Subaru they should have no option but to replace the …Aug 24, 2022 · 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.Apr 26, 2020 · I had this happen to 2006 Forester and it was running rough at idle with code showing on scanner.. Try this first: 1. disconnect the negative battery terminal for 10 minutes. 2. reconnect battery. 3. turn ignition switch to on position wait for 20 seconds. 4.2005 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 - DensoThat has fixed the P0420 code for me multiple times on several different Subies. It's a small investment compared to replacing the entire cat. ... 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.05/22/2024. When your 2019 Subaru Forester triggers a P0420 code, it typically indicates a problem with the vehicle's exhaust system, specifically the catalytic converter 's ability to reduce emissions. To resolve the issue, you'll need to identify the root cause, which could be a faulty oxygen sensor, blocked or clogged converter, or unburned ...P0420 Catalytic Converter Efficiency and C1424 ECM Module Fault are the 2 constants; they have been there every time. As a quick educated guess I am going to say the catalytic converter is failing and sets the ECM fault at the same time. ... We're the best Subaru Forester Owners Forum to talk about the best years of the Subaru Forester ...The P0420 engine code indicates the catalyst system efficiency is below the threshold (Bank 1). A P0420 code indicates a problem with the catalytic converter, more specifically. The purpose of the catalytic converter is to break down harmful pollutants created during the combustion cycle. By using fine platinum and gold meshes to filter exhaust ...P0420 is a diabolical code that IMO is best viewed with suspicion. It is only telling you that the rear O2 sensor is not getting a clean exhaust reading. ... 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. Show Less . Full Forum Listing.How does a forest fire benefit living things? Learn how a forest fire benefits living things at HowStuffWorks. Advertisement Car fueled, cruise control set and audiobook in play, I...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: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.Today we have a 2011 Subaru Outback with 174,000 miles. The check engine light is currently on and showing P0420. Does the catalytic converter need replaceme...Aug 24, 2022 · 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.You are seriously overthinking this problem. On Subarus, a P0420 code implies low cat efficiency. Your catalytic converter could actually be on it's last gasp, or it could be a variety of other things. For a 2003 vehicle, it's hard to guess exactly what's what.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 ...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, ... 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.Paid $90 for useless test. I bought front sensor off Amazon for less than $100. Installed sensor, reset code. On the second highway trip the cel trips code 0420. I rerun subaru test procedure. Results show sensors fine, bad cat. I replace the rear sensor so that when I take the car back to Subaru they should have no option but to replace the …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 ...Dec 27, 2022 · FIXD code detected was P0442 – Evaporative emission control system leak. I had FIXD clear the code prior to taking my 2005 Subaru Forester to a mechanic. The engine light and cruise control lights went out. Today a week later, the lights are back on. I used FIXD and Code P0420 – Catalyst System Efficiency was detected.The P0420 is set because the two O2 sensors are showing the same or close to the same readings. ... 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. Show Less .The '$5 fix' does not affect the vehicle's running. Despite minority grumblings to the contrary, it's pretty clear that Subaru added the rear O2 sensor mostly to be OBD-II compliant, and not much more. So, if you back it out of the exhaust stream 1/2", no big deal. Another permanent "fix" is to reprogram your ECU to ignore the P0420 code.P0420: Catalyst System Efficiency Below Threshold; P0421: Warm Up Catalyst Efficiency Below Threshold; What Does It Mean? Your vehicle is equipped with at least one oxygen sensor, and if your vehicle is newer than 1995, multiple oxygen sensors that monitor the output of your exhaust system. This sensor is designed to monitor oxygen in the ... Why not? In my experience, a P0420 is more a code to prove a bad rear O2 sensor tha

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...I have this in both my subarus more than a dozen times. Nothing was wrong with the car, the benzin (petrol) was either low octane (lower than the minimum recommended 95) or it had lead for some reason.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.Back in May 2020, I sent my Forester XT to the dealership to take care of the recall for the insufficient tightening torque of EPF nuts. The invoice states that they "INSPECTED EPF AND FOUND MANIFOLD LEAKING, INSTALLED NEW MANIFOLD AS PER RECALL, AND INSPECTED FOR LEAKS, TOPPED OFF ENGINE OIL AND COOLANT.'' Cool - I'm glad I got that out of the ...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...double check battery connections. catch-up on any any postponed maintenance. the P0420 often is due to something unrelated to the cat conv so, that should be the last thing you suspect. Exhaust leaks, vacuum leaks, weak spark.... Time Flies Like an Arrow, Fruit Flies Like a Banana! Hans747. SaveShare.The most common fix for P0420 in the Subaru Impreza is a new catalytic converter, followed by an O2 sensor replacement. Before taking your Impreza 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 Impreza: 1. Check for Other Codes.Aug 4, 2022 · How to diagnose code P0420 on a Subaru Forester. Typically, you'll find out about P0420 because your malfunction indicator lamp or "check engine light" turned on & you or a mechanic diagnosed the problem with an OBD II code scanner like this one from Bluedriver. You may experience a very slight reduction in engine power from reduced exhaust ...The OBD code p0420 is a summary code indicating that something was not quite right with the catalytic converter output at some point in the past. ... 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 engine code indicates the catalyst system efficiency is below the threshold (Bank 1). A P0420 code indicates a problem with the catalytic converter, more specifically. The purpose of the catalytic converter is to break down harmful pollutants created during the combustion cycle. By using fine platinum and gold meshes to filter exhaust ...2015 Forester Touring Key fob problems: 0: Sep 2, 2021: 2015 forester A/c problems: 1: Aug 24, 2021: Need Hatchback tent for a 2015 Subaru Forester: 0: Jun 27, 2021: 2015 2.5i Limited Forester - Head Gasket Replacement or New Engine: 0: Dec 5, 2020: Best all weather tires for a Forester 2015: 4: Sep 11, 2020: 2015 subaru /forester /4dr cvt 2.5i ...Fits Forester (2004 - 2005) EGR Valve Temperature Sensor A failed EGR Valve Temperature Sensor will often have no noticeable symptoms beyond a check engine light, but it does cause your Subaru Forester to operate inefficiently and produce higher emissions. Our technicians have access to manufacturer-approved repair processes and Subaru genuine ...Feb 19, 2008 · 31 posts · Joined 2006. #1 · Feb 19, 2008. I originally posted a question regarding OBD2 code P0133, but now I have additional info that I could use help on. Ok...there's now been one instance of a P0420 code, catalytic system efficiency below threshold (bank 1), to go along with the intermittent P0133 codes I've been getting.I have a 2010 forester with 2.5 NA motor. I swapped motor bc rod bearings spun. There was a misfire . We replaced plugs, both cats, both o2 sensors, MAF, and leaky EGR.. Car runs great now, BUT, i have check engine, traction,cruise light combo. Oil level is good, motor smoke tested, no leaks... I have a P0171 and P0420.Jan 14, 2022 · That's one of Subaru's plans to make you fix your car instead of ignoring the code. In my experience the P0420 code has always been fixed (4 times on three different cars, and the second time on one car was the other bank on a 3.6R) by replacing the downstream O2 sensor. Did you replace it with a good brand-name sensor or whatever you found ...Forester: check engine light (and cruise light) on after replacing the timing belt. Mechanic says it is the catalytic converter and cost to replace is about $1000 (upstate NY) Report. 2000 Subaru Forester 185,420 mi, Visitor. light is on and i dont think its my cat. think it might be the O2 sensors.. checking it out.My P0420 code started this past February and it has been driving me crazy. I started with replacing the pcv, code still there, then I used the Seafoam method. That cleared the code for a few weeks just enough to help me pass my inspection in August. After that the code has been coming on persistently.48 posts · Joined 2009. #1 · Apr 19, 2009. P0420: Catalyst efficiency below threshold (bank 1) P0171: System too lean (Bank 1) P0171 Pb: system too lean (bank 1) These are the codes i pulled today, and what do they mean. 2004 WRX with 50,781 miles, perrin short ram intake and axle back exhaust.We just took care of two recent recalls - valve spring recall and faulty brake light switch/ABS/VDC recall - at a Subaru dealership a couple of months ago. The PCV was also replaced which seems to have stopped excess oil consumption. ... I have a 2014 Forester with 133,000 miles. Recently got the Christmas Tree dash of AT oil temp, hill assist ...Most common causes for the P0420 code: failing oxygen sensor, exhaust leak, cat. failure. The first two are much more common and much easier to fix. If these don't fix it, then look at the cat. 2002 Outback wagon 3.0 L.L. Bean no more: " Mal ". 142,000 and counting. Mismatched cloth interior swap.The P0420 code has not repeated so far driving it normally under all sorts of conditions. I am still hesitant to call it "fixed' however in the past I would have been able to get the code by now with how I have been driving it. ... We're the best Subaru Forester Owners Forum to talk about the best years of the Subaru Forester, modifications ...The codes are: P0420: Catalyst System Efficiency Below Threshold (bank 1) P0422: EVAP Control System Leak Detected (Small Leak) I am now in a new area and went to a mechanic who wasn't familiar with my vehicle history. I explained my situation and mentioned to Rear O2 sensor issue of the past. This mechanic read the codes and said that it was ...P0420 is a diabolical code that IMO is best viewed with suspicion. ... We’re the best Subaru Forester Owners Forum to talk about the best years of the Subaru Forester, modifications and reliability history of the …My '11 Foz has popped the dreaded P0420 and given that she's at 162k, ... We’re the best Subaru Forester Owners Forum to talk about the best years of the Subaru Forester, modifications and reliability history of the …P0420. I have a 2004 Legacy 2.5 California spec (3 cats, 5 O2 sensors) with a recurring p0420 pending code on bank 1 that keeps popping up on my blue driver for the past 2000 miles. The cats were replaced under warranty about 8-9 years, 100,000 miles ago. The Oxygen sensors are all original, so they have 167,000 miles on them.Subaru Forester Owners Forum is a community of enthusiasts who share their experiences, tips, and advice on the best Subaru Forester models, modifications, and reliability. Join the discussion, browse the forums, …2010 Subaru Forester, with P0420 Code. Dealer states the Catalytic converter needs replaced. Question is whether the converter in the pretzel style exhaust line can be replaced without replacing the d … read moreNov 3, 2007 · 35 posts · Joined 2007. #1 · Nov 3, 2007. Two weeks ago I had to have the front O2 sensor replaced on my 2000 Forester. Just last night I got a CEL and went to Auto Zone to check the code. It was P0420 Catalyst Efficiency Below Threshold. Sounds to me like I may have been given a bad sensor at the repair shop or the back sensor is now bad.P0420 is a diabolical code that IMO is best viewed with suspicion. ... We’re the best Subaru Forester Owners Forum to talk about the best years of the Subaru Forester, modifications and reliability history of the …May 29, 2023 · 2.5x_sleeper. 45859 posts · Joined 2007. #5 · May 29, 2023. @Highest_Harvest looks like low end is around $300, upward to over $500 on RockAuto, as the front CAT & headers are one piece. Normally a P0420 CEL code is caused by too much O2 in the exhaust flow from the engine running too rich.seaholmes said: 2014 Subaru 160k 2.5 l engine. Recently had a promotion at my local oil change shop, where was recommended to take advantage of fuel injector service special. The technician used my brake booster hose as the vacuum to draw in the cleaner, to I assume my intake manifold. Sucking something into the intake manifold is not going to ...Causes of the P0420 Code. Several issues can lead to the P0420 code in a Subaru Forester. Here are the most common causes: Failing Catalytic Converter: The most direct cause is a catalytic converter that is no longer effective. Oxygen Sensor Malfunction: Faulty oxygen sensors can send incorrect data, leading to a P0420 code.The '$5 fix' does not affect the vehicle's running. Despite minority grumblings to the contrary, it's pretty clear that Subaru added the rear O2 sensor mostly to be OBD-II compliant, and not much more. So, if you back it out of the exhaust stream 1/2", no big deal. Another permanent "fix" is to reprogram your ECU to ignore the P0420 code.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 ...Why not? In my experience, a P0420 is more a code to prove a bad rear O2 sensor than an actual innefficient cat. How do I know? I threw a P0420 constantly in my …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!!I have a 2010 non-turbo with 113,000 miles and was getting P0420 codes which are common and did the "$5 fix" with the O2 sensor and the P0420 codes have gone away. ... 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.Aug 4, 2022 · How to diagnose code P0420 on a Subaru Forester. Typically, you'll find out about P0420 because your malfunction indicator lamp or "check engine light" turned on & you or a mechanic diagnosed the problem with an OBD II code scanner like this one from Bluedriver. You may experience a very slight reduction in engine power from reduced exhaust ...P0420 Catalyst System Efficiency Below Threshold; P0171 System Too Lean; P014D Manufacturer Defined - O2 Sensor Slow Response - Lean to Rich (Bank 1 Sensor 1) ... Forester Owners Forum to talk about the best years of the Subaru Forester, modifications and reliability history of the Subaru Forester. Show Less . Full Forum Listing.P0420 is catalyst below efficiency. P0303 is misfire on cylinder 3. The misfire could be contributing to the catalyst problem so it should be addressed first. Pull the # 3 plug and look for carbon or wet with gas. The old plug wires are also suspect. Clean the plug and re-install. Check the connections on both ends of the wire.UK '01 Manual All Weather Forester. The annoying P0420 reappears between 70 and 200 miles. ... 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. Show Less .My 2013 Subaru Forester with 144k miles just got this P0420 code today. I went by the auto parts store and they gave me a printout that it's the catalytic converter. ... Failing O2 sensors, especially on newer cars, 99.9% of the time never throw a P0420. The P0420 means the computer detected a specific correlation between upstream (pre-cat) and ...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. Technical Forums and Vehicle Assistance. Engine and Exhaust. EJ25 - 2.5L Non-Turbo (1998-2010)

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