P0420 subaru wrx

P0420 subaru wrx. 5 and CVT. Have always used mid-grade gas in the car, and am religious about oil changes, etc. I am pretty confident the dealer that sold it to me cleared it so it wasn't noticeable if you didn't know to look for it when you test drove it. May 7, 2023 · I am new to this forum. First one was a P1604 (Startability Malfunction) which they told me the solution from Subaru USA was to just clear the code. Free Same Day Store Pickup. I’ve had Jpipe installed for about 3 months and exhaust for a year or so. It's one of those annoying things that make it a subaru. Outback, Forester, Baja, WRX&WrxSTI, SVX ; CEL throwing P0420 code Theme A slight leak in the exhaust system can cause this,oil consumption or improper fuel mixture is the leading cause of failure, make sure the code is current , do not erase the code the freeze frame data stored may help the dealer. 2% efficiencyenough to throw me a code. Correct me if im wrong but all Cobb downpipes are catted and have that high flow cat in them. Whenever oxygen content is low (rich) a large electromotive force is generated. When you receive a P0420 code it means your catalytic converter is not operating at maximum efficiency. Thanks for the help. (Going to do that this weekend), I generally do all the basic maintenance myself like fluids and follow the Nov 6, 2021 · This Subaru Outback has a P0420 Again! This catalytic converter was replaced two and a half years ago and the light is on again for catalytic converter ineff May 16, 2022 · Maximus1991 Discussion starter. This subheading aims to provide a detailed explanation of what the code means and its implications for the vehicle. That's what it's suppose to do & doesn't always mean the CAT or rear O2 sensor is bad. This has always happened when I'm driving at a constant speed with Cruise on. Ongoing issue: Sensor still throws a "below threshold" code now and then - particularly when on long drives. #1 · May 16, 2022. While you're at things, Replace your ignition coils. I'd like some other opinions, though. about two weeks ago the check engine light went on and threw the p0420 code. hi all. It looks like it is catless and has one O2 sensor. Feb 14, 2023 · In this video I am working on a 2014 Subaru Outback with a 2. while at work i did scan the car and i found rear o2 sensor to jump around between 0. There is lots of conversation about the P0420 code - but I am not prepared to replace the converter - but really want to get the cruise Jan 25, 2017 · Engine/Traction Control on, Cruise blinking code P0420. Jan 6, 2023 · P0420 code highlights. Stage 1 and 1+ Cobb ots tunes never had any codes disabled by default, green speed or otherwise. It can also be caused by an exhaust leak or a bad oxygen sensor. A non-commercial subreddit devoted to the VB chassis 2022+ Subaru WRX. Homebrewed tuned with Opensource! Mar 17, 2023 · P0420. It recently threw a CEL for P0420, Catalyst System Efficiency Below Threshold (Bank 1). Jun 30, 2021 · 2015 wrx P0420 code. It has to do with the emissions system and stands for Exhaust Gas Recirculation (EGR)→ Insufficient Flow. Mar 15, 2013 · I got the dreaded p0420 on my 04 WRX Wagon that I got about 9 months ago. Drive till empty. By using fine platinum and gold meshes to filter exhaust Mar 9, 2022 · *I take full responsibility for what happened!*I decided to document my process of diagnosing and correcting the car's air fuel issues. recently iv been getting it a lot (once a week or more). P0401 is a very common OBDII trouble code that’ll pop up in the Subaru WRX. Mar 13, 2023 · NOTE: Take note that while the cods listed below are not strictly related to P0420 – “ Catalyst System Efficiency Below Threshold (Bank 1)”, these codes often appear with P0420. there is no known relationship between the battery and the p0420 code. MIL came on around 6 weeks ago with a P0420 code. my dam has been dropping when I don't clear the Apr 6, 2010 · Pesky P0420 Code on an '04 WRX. 2005 Forester XT stock except for my son added an Invidia turbo back exhaust. I have a 07 Outback wagon which has had the CEL on for the past 2 years. It's throwing a code P0420 which is P0420: Catalyst System Efficiency ***8594; Below Threshold ***8594; Bank 1. It is one of the most common emissions-related codes and can be caused by a few different things. And always remember, an A/F and O2 sensor NEVER reads HC levels. I have been clearing the code but it keeps coming back. Ran my OBD2 scanner and turns out I have a catalytic converter code failing code (P0420). ago. #1 · Oct 17, 2010. 6v when the CAT is lit. Dec 4, 2007 · I have been trying this on quite a few subes with the P0420 catalyst insuffiniency code and it has worked great. Subaru & Honda. Oct 10, 2012 · Well you can search "Subaru P0420" on Google to get more ideas or get ahold of the factory service manual and read the OBDII diagnostic section. What Does the P0420 Code in a Subaru WRX Mean? Jun 6, 2017 · P0420 is Catalyst System Efficiency Below Threshold (Bank 1. It's likely one of the oxygen sensors. To quickly reset the ECU, remove the negative battery terminal, secure it, set up on the brake pedal for ~10 sec to discharge any left in the system. If it’s not a gesi cat it will most likely pop up. Jump to Latest Follow 1 - 7 of 7 Posts. ? my car isnt in limp mode right? thanks for any feedback. Has anyone dealt with P0420 code? if so, what was the cause of the problem so i can narrow it down? any suggestions on how to test 02 sensors? thanks! will an STI up pipe and down pipe bolt onto 04 wrx? Yes but the STi uppipe is the only thing that is different than your stock parts. The "Reflash" map should be the map with the most appropriate tune (stage 2+) with P0420 disabled. I'm assuming the code is from a bad 02 sensor since the downpipe only has a single sensor connected before the cat (the May 9, 2012 · Tech & Modifying & General Repairs. bad would be head gaskets. Hello, so i installed my new K&N [69-8006TTK] intake on my 2017 WRX today, and when i turned my car on, the check engine, abs, VDC, and hill assist lights came on. The following have been successfully done: Full engine rebuild (new pistons, bearings, gaskets. Saab, Subaru: Exhaust gas recirculation (EGR) solenoid valve – signal 2 – voltage low P0420 - Catalyst System Efficiency Below Threshold Bank 1. I would wager that the P0420 code was disabled in the rom due to a downpipe or bad CAT and when you flashed that Cobb Stage 1 map, the code was re-enabled and tripped. Mar 25, 2021 · Abs, hill assist, traction, engine light on after K&N intake install. It is a simple fix that can be done in minutes. i intsalled my downpipe 2 weeks ago and i just barely got a cel (p0420). If you can extend the length of the handle with a piece of pipe, the longer the wrench will give you more leverage. May 17, 2020 · Today we have a 2011 Subaru Outback with 174,000 miles. When the oxygen content is high (lean) a small electromotive force is generated. 2019 FA wrx. 3 tanks in a row. Feb 15, 2006 · It has the property of generating electromotive force when contacting oxygen. It is the P0420 code and I had it confirmed it is the catalytic converter (not O2 sensor). Here’s a good P0420 diagnostic order for the Subaru Tribeca: 1. Nov 13, 2019 · 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. I didn't erase the code that was stored. Would like to keep the car for my teenage son, who will start driving this summer. Does ALL check engine light trigger the performance “limp mode”? I have always wondered that, is it only specific “banks” of codes that trigger the performance restriction, or apply to all? I. Pressing control buttons had no effect. that code is usually related to the o2 sensors, not bad cats. Check for vacuum leaks or other fuel mixture-related engine codes. 677 posts · Joined 2021. Dec 7, 2014 · 2006 Subaru WRX TR (Summer Ride) 4cyl 2. The code "appears without reason" sometimes. I'm seeing the P0420 code as well (all stock 2005 Subaru WRX STI). P0011 is a common (and serious) OBD II diagnostic trouble code that can occur in the Subaru WRX. 2 questions I have are 1. Feb 5, 2008 · 2841 posts · Joined 2004. Maintenance, service, and repair Sep 1, 2013 · Looking to disable P0420 code so cruise works. the works) - No mechanical issues. If you're looking for a buy/sell/trade group, check out r/VB_WRXMarketplace. : r/WRX. Jul 18, 2021 · I know that individually the P0301,P0303 & P0305 are cylinder misfire codes. When i put it on the scanner it came up with P0172 so i cleared code and bought up and down stream o2 Sensor. May 11, 2017 · So my wife and I bought an '07 Outback Basic back in January, used with about 130k miles on it. In this case it's not, but it may or may not be the catalytic converter itself. 5i 105k on the clock, no engine mods. The main reason why I Nov 26, 2010 · The code P0420 in the Autozone readout specified bank1 so I took a chance on the mod for just the sensor behind the passenger cat since AZ only had one package in stock. i noticed no problems with performance. For the past several fill-ups, though not every time, the CEL and Traction Control will come on and the Cruise Control blinks. ever overheat ? Apr 13, 2015 · When you go to change maps, make sure you are selecting the reflash option and not the realtime option. Hello i have a 2012 WRX Premium with 80k miles recently i had a check engine light come one. Level of urgency:Medium; Possible culprits:catalytic converter, exhaust pipe; Price for repair:$500 - $1,500; If neglected:Engine stalling, power loss, failing emission tests; DIY repairs:Impossible; Can you drive?Yes . I had some work done on my 2017 STI recently, and the mechanic that worked on it mentioned that it is due to the ACT XACT Prolite flywheel that was installed. He recommended installing a fluidampr to help with the Aug 31, 2022 · PhoSho. or a o2 sensor. Check for Other Codes. i noticed a bit of a rough idle since i test drove it, but i figured it was something minor that a sparkplug change would fix. Ok, that sounds right. Members Online Jan 10, 2023 · The P0420 code is a Diagnostic Trouble Code (DTC) that indicates an issue with the catalytic converter on a Subaru WRX. Cat efficiency code, nothing to do with your tuner. On a stock vehicle it is a little harder to diagnose over the interweb. #3 · Feb 23, 2012. 45-. Mar 9, 2010 · P0420 code. He turned the car off and they were gone but came back the next day. Jun 7, 2013 · I would check spark plugs and for any air leaks pre-turbo side. It indicates an issue with your car’s Variable Valve Timing (VVT) system. I am in the process of dialing in an Etune from Drunkmann. The most common issues are related to the exhaust system, such as an oxygen sensor that has gone bad or a leaking exhaust manifold. A P0420 code indicates a problem with the catalytic converter, more specifically. #2 · Feb 6, 2008. Clearing the code doesn't make it go away. You should see a steady . Then reconnect the negative battery terminal. P0420 right off the bat, multiple tune revisions didn't help. com. Chapter/Region: TXIC. So I have a 2015 wrx with 96500 miles. Car from what I can tell drives/runs fine. I would get it fixed soon as ya can. Mechanical Help. Ask Your Own Subaru Question. Tutorials & DIY. I'm seriously thinking that the problem is not a cat problem, but an O2 sensor problem. So, my car's been through a few entire I/M readiness cycles, and just twice the CEL has come on with P0420. The rear O2 sensor would behave almost like the catalytic conver P0420 means the downstream (post cat) O2 signal sent to the ECU is outside of acceptable range when compared to the upstream. When the OBD system detects that the catalytic converter Apr 29, 2022 · Chapter/Region: NESIC. it does have a axel back exhaust on it. Go to your local auto parts store and get a long 18mm spark plug non fouler, drill the end with the small hole out with a 1/2 in drill bit to allow the thimble of the o2 to fit through. 3. Spray the cold sensor with some PB Blaster. 3K members Since 2001 We invite you to join our Sep 12, 2011 · All Activity; Home ; Newer Generations of Subaru discussion ; 1990 to Present Legacy, Impreza, Outback, Forester, Baja, WRX&WrxSTI, SVX ; P0420 Apr 4, 2016 · These things happened after running over a small tree branch with my 09 Impreza. Which gave me a heart attack because it's a Subaru. How often will this cel keep popping up after I reset? 2. Essentially it looks at the values of both and determines if the catalytic converter is working efficiently or not. If you find a P0420 code in your Subaru or Honda, it’s most likely the catalytic converter to blame. 1329 posts · Joined 2014. My fuel economy has tanked and I get an intermittent P0420, always when driving at highway speeds. Here's my story After nearly a dozen resets using a scanner tool, I observed that the CEL would only trigger after the car had warmed up and I was cruising at ~55 MPH. Vehicle: 2021 WRX BASE. Nov 30, 2018 · The most common fix for P0420 in the Subaru Tribeca is a new catalytic converter, followed by an O2 sensor replacement. If the oil level is too low, the camshaft actuators won’t work All, Only engine mod on my car is an INVIDIA cat-back. Could this work? (Greenspeed & p0420) Since the new Cobb greenspeed update made it so tuners can’t disable the p0420 code that people get after running an aftermarket down pipe could someone just use a defouler on the secondary o2 sensor to make it not trigger the code? I just learned about people using the /r/WRX is a place for Subaru fanatics to show off their rides, discuss modifications, mechanical issues, industry news, and more. fst8nuff · Registered. Here’s a good P0420 diagnostic order for the Subaru Impreza: 1. Joined Oct 13, 2011 · 16 Posts Find your TRQ parts here: http://1aau. Came on about 200 miles after I bought the car. 2002 Forester 2. May 17, 2023 · Conclusion. 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 Apr 8, 2011 · P0420 Cataylisy system efficiency below threshold (bank 1) Jump to Latest Follow Subaru WRX Forum. Apr 2, 2013 · 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. Sep 6, 2017 · Jay11STI. Nov 19, 2017 · However, on long trips or when the car is driven exceptionally easily (stay in the far right lane, cruise 55-65mph, super light throttle inputs, basically hyper-mile type stuff), I get a check engine light for code P0420 (Catalyst Efficiency Below Threshold) after about 10-20 minutes. #1 · Aug 24, 2023. Okay my brother has 2011 WRX, he was driving and the ABS, traction control, and hill assist lights came on and stayed on. AFR is at 14. G. 5XT EJ series was getting the p0420 when I had a Jul 22, 2018 · VSurfn. /r/WRX is a place for Subaru fanatics to show off their rides, discuss Nov 28, 2014 · I have an '09 2. Today the flashing CEL and cruise control came on. What are your modifications? Aug 30, 2007 · downpipe = cel p0420. It's all Subaru. I tried pressing and holding the traction button for the hill assist light but it doesnt work. Dec 8, 2021 · I have a 2019 STI that was pro tuned with a grimmspeed downpipe and a cobb sf intake that I recently purchased. Oct 17, 2017 · I've been to the service center twice with two different CEL codes. I have a P0420 on my 2015 WRX with 131k miles and here is what I've done so far: Replaced both O2 sensors. Check out free battery charging and engine diagnostic testing while you are in store. I cleared a P0420, and none of the lights came back. After every timing belt job P0420. ”. It specifically refers to a “Catalyst System Efficiency Below Threshold” in Bank 1. Location: Lake George , New York. Before taking your Tribeca into an exhaust shop for an (expensive) new catalytic converter, let’s ensure that’s what you need. They can no longer delete that code due to cobbs green speed initiative. If the rear is producing crossout sinwaves, like the readings you are seeing for the front, something is wrong. Before that it was Jun 26, 2012 · P0420. We invite you to join our Subaru Impreza WRX and STi community to discuss engine mods, builds, detailing, and more. We have done quite a bit of work to this car to solve an ongoing P0420 code. Hello all! I have a 2021 wrx with 20k miles. 1-0. Car is pro tuned at the moment. So I decided to investigate. To verify what reflash and realtime maps you are running, go to the Tune -> Show Current Map menu on the Accessport. Oct 17, 2010 · 1232 posts · Joined 2010. Barry, snake2332 and 405HP_Z06. 3) O2 sensor voltage with cold engine (all over the place) 4) O2 sensor voltage from acceleration (big variations) 5) O2 sensor voltage with a warm engine while maintaining speed/RPMs (front is sporadic while rear is consistent, hoping this means cat is still good Jun 12, 2019 · Ah the classic Subaru P0420. Red. oil loss and P0026/P0028 could be serious issues - you may have oiling issues which can essentially render an engine useless very quickly. I'm having an intermittent engine light on my '11 Limited. 5 Outback for about 6 months solid now. So are parts required to fix this pesky emissions code? In this case we get a good example of where the "money light" gets its n Feb 22, 2012 · 1390 posts · Joined 2011. Order Subaru WRX Ignition Coil online today. The 0-1v readout that most other cars have, does not apply to Subaru. r/WRX. My daily driver 2019 WRX STi has 65k miles and is bone stock. I've tried using the anti-foulers, and even the electronic fixes in the rear Dec 9, 2018 · October 13, 2022 by Jason. Doesn’t really effect drivability. Fill tank full of premium 91 or 93 and put the entire 3L jug in there. Mar 31, 2011 · On many Subaru's its actually easier to replace the 02 sensor than the 4 spark plugs. The sensor is operating at 100. 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. Mar 21, 2024 · 3. Replaced engine filter. jake5990. So , last month I installed my Invidia catted j pipe and with it the Cobb stage 2+ big sf intake on my 2021 WRX 6-MT . C0042 Subaru Code - Power Supply Voltage Failure. P0422 – “Main Catalyst Efficiency Below Threshold (Bank 1)”. The car is bone stock. Mar 23, 2024 · The ECM controls the heater element circuit by allowing current flow to ground. . :wink: I'm not sure if the P0440 - Evaporative Emission Control System Malfunction, is related to the P0420 - Catalyst System Efficiency Below Threshold. • 1 yr. It is drive by wire and has the California emissions on it. As a result of this, I found several other issues with my 2016 WRX (manual transmission), and fixed them. May 31, 2023 · Subaru runs a wideband O2 in the front. 2M posts 153. I have a question that hopefully someone can help me with. I have a 2004 OBW and it keeps throwing the P0420 catalytic system below threshold code. Alright, I got the intermittent CEL for the pesky P0420 Catalyst System Efficiency Below Threshold (Bank 1). Usually this means your catalytic converter needs to be replaced and/or your O2 (oxygen) sensors. When trying to remove the sensor, do it after the engine/exhaust has warmed up. But what would cause all three in one bank of cylinders to register a misfire at the same time? Thanks in advance. Has to do with the rear O2 sensor. May 14, 2015 · This low kilometer Subaru Impreza flags a P0420 Catalyst efficiency fault code very quickly. Jul 29, 2020 · Need help with P0300 and P0000 codes. The purpose of the catalytic converter is to break down harmful pollutants created during the combustion cycle. The EGR system in your car is responsible for recirculating exhaust gasses in order to lower the vehicle’s emissions output. The technician mentioned there is no check engine light at 100 Feb 22, 2015 · 2018 wrx showing “pending codes” of p0420, p0137 and p0296 with a rare occurrence of p2196 Jump to Latest Follow JavaScript is disabled. Does the catalytic converter need replaceme Even if your car is stock you can still get p0420. MTpuckstopper Discussion starter. 9 posts · Joined 2023. I installed Down Stream o2 sensor and when i went to install upstream it was the wrong connector so i i purchased a 2015 wrx premium with 62k miles back in december 2022. Code P0420 and P0137 after Invidia Catted J pipe install on 2021 wrx. This thread also applies to other makes and models when it comes to diagnosing a P0420 and the root cause for the lack of efficiency on the cat's part so the info here can be used with other vehicles, even German cars. . Feb 17, 2009 · It is called a "Spark Arrestor" and is a metal piece that screws directly into where the O2 sensor goes, and then the O2sensor screws into it. Make su Dec 2, 2018 · November 25, 2022 by Jason. Unmetered air would make it go crazy. The Anti-Lock Brake System (ABS) Module monitors the Power Supply Voltage. Pure Red. I thought maybe a wiring issue--your thoughts? May 27, 2017 · Common cause of P0420 is an exhaust leak but mine had none. P0420 indicates a failing catalytic converter. My gas mileage has dropped from mid to high 27's to low 24's today on my way to work i threw p0420 cat efficienty. The ABS Module sets the OBDII code when the Power Supply Voltage is not to factory specifications. The rear O2s are the standard 0-1v units. Code should go and stay away for the foreseeable future. My 2015 is almost exactly 2 years old with 36,500 miles and engine/exhaust/fuel system is all stock. I have a Grimspeed v2 gesi catted j pipe, remark catback as well. The P0420 code is an indicator of a problem with the catalytic converter in your Subaru. The first thing you should do when you have this code is check your WRX’s oil. The P0420 code is a common issue that many Subaru Impreza owners experience. Feb 28, 2009 · 2003 wrx code P0420. Replaced MAF sensor. definitely ignore that for now, you can drive a car for 100,000 miles with that code, no big deal. I checked the code and it was a P0420 catalytic converter inefficiency. The check engine light is currently on and showing P0420. P0420 is generally a universal code for Catalytic Converter limit below threshold or something along those lines. You car should still be under warrenty right?For the 32 bit ECU cars (All STi's and 06+ WRX) this sensor is kinda important. 2) AF ratio charted with O2 sensor voltage. Mar 31, 2022 · Check Engine codes P0172 now P0420. Replaced downstream 02. Can be purchased for about $25 at fastwrx. Only O2 levels. The most recent one was a P0852 - Park/Neutral switch malfunction. #8 · Sep 9, 2017. The P0420 code signifies a problem with the catalytic converter efficiency in the exhaust system of the Subaru Impreza. Mar 14, 2013 · Silver. It's best to take your vehicle to a professional mechanic for diagnosis and repairs. Show Less . Bank 1 refers to the side of the engine where the number 1 cylinder is located. r/subaru • 2019 Jun 13, 2006 · I don't mind if you post up questions about a WRX, Forester, Impreza, what ever. P0420 daily . but an exhaust leak can cause it as well. Vehicle Details: 2005 Forester XT. The ECM monitors the voltage signal received through the heater element circuit and determines the state of the circuit by comparing the voltage detected with the factory specifications. No fluid leaks of any kind. Went stage 2, etuned, catted grimmspeed dp. its stock and all I have done is a stage 1 ots tune by cobb. If the code returns, I will do the driver's side as well as the rear sensor behind where the dual exhausts join, hopefully on a warmer day. I also have a remark mid pipe and axle back muffler delete installed . Jul 19, 2014 · P0420 is benign or simply and artifact of the poor running engine. And again. to/m/ETCG0420Eric the Car Guy is here! He's visiting TRQ to explain check engine codes to you! In this video, Eric the Mar 28, 2009 · The P0420 is from the rear O2 sensor detecting too much oxygen in the exhaust. P0423 – “Heated Mar 9, 2017 · The pictures show: 1) general info. maybe a fuel rail issue though. #7 · Sep 3, 2022. After a day's worth of stop/restarts, the problem disappeared. 2011 WRX showing Traction Control, ABS, Hill Assist Lights. I am looking to sell it, however very recently I got a CEL, tire pressure warning light, traction control light, and cruise control flashing light all pop up at once. It could be the catalytic converter, too. Aug 16, 2022 · In 2021, I had a lot of fun working to track down a P0420 code. Buy the 3L jug of cataclean. Sent from my magic banana The P0420 fault shouldn’t be causing that significant of an impact on your boost numbers. Autozone will lend the O2 sensor removal wrench. ) I have looked at many past threads on this but wanted to share my experience with this DTC which recently caused my CEL to come on. The CEL codes (P0420, P013 May 7, 2023 · The P0420 code is a generic powertrain code that indicates a problem with the catalytic converter in the exhaust system. I have been getting this code for a while now since November. e, My Forester 2. so after research i learned i need a cel fix or i can just drive the car with the cel on right. Aug 5, 2013 · Join Date: Apr 2011. r/WRX • 2019 WRX P0420 to P013F. from what i can tell the muffler is a Hey everyone!So the Subaru WRX decided to give me a check engine light (CEL). :screwy: Generally, I can reset the CEL code and continue on; however, I think that I have a bad oxygen sensor. 5L Turbo DOHC 94k miles I have had the P0420 code on my 2008 2. In 2005, Subaru switched to an ECU that uses the input from the rear O2 sensor to affect fueling in addition to simply monitoring the cat (as in 2004 and older cars). Vehicle: 2005 Impreza WRX. Location: Denton, Texas. P0420 is catalyst system below threshold bank 1 this could be the bank one oxygen sensor or it could be the catalytic converter. Just had shop try to address the P4020 code without success. Result: 95% reduction in cell code alerts. 5 AT. I have a 2013 hatchback wrx with 105k miles. Common causes can include failed or malfunctioning components, such as the oxygen sensor, fuel system, EGR system, and exhaust system. P0421 – “Warm Up Catalyst Efficiency Below Threshold (Bank 1)”. the car has around 85,300 miles. ok ive done the research just want a confirmation on my findings. i got it 3 days ago and this morning i got code P0420. Both times it's been on a highway in the rain. Maybe the sensor is bad,shorted wire, or unplugged. The car is running fine, but I have yet to change the spark plugs. Aug 29, 2021 · P0420 rear o2 sensor. #1 · Jan 10, 2012. Didn't realize the nightmare it was or I would have gone striaght back to them. Nov 26, 2010 · While on some cars they do actually prevent the P0420 DTC from being thrown, they cause fueling problems on all cars 2005 and newer. Hi all, my question is regarding codes P0300 and P0000, both are for random cylinder misfire. 46 posts · Joined 2021. Nov 30, 2018 · The most common fix for P0420 in the Subaru Impreza is a new catalytic converter, followed by an O2 sensor replacement. Jan 10, 2012 · 63 posts · Joined 2011. It's engine is a model EJ259 if I remember correct. i'm new to subaru vehicles and my 2003 wrx wagon is my first. 7v. Before taking your Impreza into an exhaust shop for an (expensive) new catalytic converter, let’s ensure that’s what you need. P0420 again. Check for any exhaust leaks before the catalytic converter. #2 · Jul 22, 2018 (Edited) P0420 code stands for “Catalyst System Efficiency Below Threshold (Bank 1). 3581 posts · Joined 2011. I failed emission tests after unplugging the battery and driving 100miles. P0037 Subaru Code - HO2S12 Heater Control Circuit Low. Went from 35 miles before CEL to about 100 before kicking off. 7 while driving. P0441 - EVAP System Incorrect Purge Flow. The P0420 engine code indicates the catalyst system efficiency is below the threshold (Bank 1). i haven't checked for exhaust Aug 24, 2023 · M. when i was on my way to the dealership, the light went off so they said they cant fix it under warranty and it’ll be May 2, 2020 · Description. Nov 30, 2023 · After every head job P0420. ai tq em sy zn tc xc mc yk yh