I have the ability to reset the code but it keeps coming back any idea what other parts i could replace. Other thread in "problems and solutions" M. Jul 1, 2011 · The P0420 code is a very popular one and that's why there's a site dedicated to that specific trouble code. Increase the gap between the oxygen sensor and the converter using a spark plug non-fowler. . My friend owns an auto repair shop and he put the #1 and #2 O2 sensors on the diagnotic screen while we drove around (I drove, he watched the screen) to determine that the O2 sensors were May 4, 2017 · Just 0420 code I've reset it multiple times and it keeps coming back. But no matter what, they agreed to fix the problem for the money you paid them. Chad Farhat. Youll get codes for o2 sensors if theyre bad. Aug 3, 2019 · 1998 Camry 2. We did some research and it looks like the catalytic converter. This code was P0420 and after reading online I thought I would replace the cat and the o2 sensor that plugs into the cat. You’ll likely find an expert who’ll suggest a perfect Toyota P0420 fix for your car. Mar 31, 2024 · What Causes A P0420 Trouble Code? As mentioned earlier, the cause of the P0420 trouble code is a failing catalytic converter. Here are a couple of the parts to take a Jan 1, 2024 · Equinox p0420 properly smarter 2012 chevrolet equinox 135,000miles 2. The most common of these is a faulty catalytic converter. Solved issue. I later tried the Dura Lube catalytic converter cleaner sold at Wal-Mart. I had driven the car for about 6-8 months with the thermostat open before replacing. About every 300-500 the CEL comes on P0420. It can be caused by various issues, ranging from faulty oxygen sensors to engine misfires or fuel system issues. Sep 20, 2018 · Honda Pilot P0420 Code Symptoms. Catalytic converters/catalysts break down over time and can also become clogged. Downstream oxygen sensor (HO2S) wiring damaged or connected improperly. Sep 21, 2009 · 2001 buick regal 3. The check engine light went out but came back with the same po420 code after a couple hundred miles. At 125k the Cat was replaced (direct fit). It started with just bank 2 at first but now it is both. Before taking your Cruze into an exhaust shop for an (expensive) new catalytic converter, let’s ensure that’s what you need. 2l 5sfe and I replaced the thermostat. I suspect the cat may be clogged now though. The latter also helps determine the efficiency May 19, 2021 · Diagnostic trouble code(DTC) P0420 stands for “P0420 Catalyst System Efficiency Below Threshold (Bank 1). said that front sensor doesn't read the same way since it's a wideband air/fuel and reads in amperes not volts. That didn't fix it and than the bank 1 code for the cats started coming in. 1A 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. Ive never seen o2 sensors cause it in my time. 02 sensor down stream was replaced at 135k used a Bosch Smartlink. P0420 at 210k miles on my wife's 2003 Prius, changed cat converter (June 2014) with one from Eastern Catalytic (p/n 40544), had 4 months and 15k of trouble-free driving, and now (mid November, 2014)the code is back. No code for 2 years, then downstream o2 sensor falls off. Campaign 14801A (Emissions Reflash) was completed at GM dealer. Image3 jpeg chevyP0420 chevy equinox issue and solutions to fix Mar 23, 2021 · There is a p0420 thread on the acadia forum now. The long term fuel trims and checking how the engine is running should be able to tell us why the converter efficiency P0420 code keeps coming Nov 30, 2018 · The most common fix for P0420 in the Dodge Ram is a new catalytic converter, followed by an O2 sensor replacement. p420 is typically a bad cat converter. P0421 – “Warm Up Catalyst Efficiency Below Threshold (Bank 1)”. Aug 25, 2020 · JOIN GASDIESEL GARAGE AS WE DIAGNOSE AND REPAIR THE MOST COMMON CHECK ENGINE LIGHT TROUBLE CODE P0420 Catalyst Efficiency Below Threshold Bank 1 SENSOR 2 ON Mar 1, 2017 · HI, While the common thinking on this code is the rear converter, which in most cases is true, in this case, it is the Bank 1 converter that bolts to the exhaust manifold. 180K miles, p0420 code, have cat temp-front in 421F out 442; rear in 312F out 355://Front AFR(Advance AP replacement with 80K miles on it) sensor heater ohms1. I have a 2014 Cruze LTZ which is showing a P0420 code. Jul 12, 2023 · 420 code, keeps coming back. Jan 16, 2016 · The customer returned after the catalytic converter was replaced and the P0420 reset. Customer comes in needing a cat (in addition to what caused it to fail), we quote it, they tell us to pound sand, they go to the Mobil gas station mechanic who replaces the cat for 1/3 the price, they return complaining the light came back on after a brief period of time because the gas station mechanic told them to go to the dealer. You need to inspect the cat converter internally to determine if its damaged or not. 0 engine . So, your Check Engine light is on, and you’ve got either a P0420 or P0430 code, on your OBD-II scanner. In detail: The P0420 code specifically points to a problem with the efficiency of the catalytic converter. So I broke down and drop $1100 to replace both cats. May 4, 2016 · 1742 posts · Joined 2012. 2012 Chevrolet Equinox 135,000miles 2. Sep 28, 2022 · In this video, you'll learn the causes and solutions of the P0420 code. 7,MAN. 2003 Trailblazer 4. 4L P0420 Keeps coming back. Feb 22, 2011 · Rochester, NY USA. Needed a new catalytic converter. Nov 3, 2021 · The 420/430 are saying Catalytic converter system, efficiency below threshold for both sides. 21 posts · Joined 2015. Check Engine Code: P0420. 2. 1772 posts · Joined 2015. They all were repeating p0420 & p0430 codes . 2L 188,000. There are rarely drivability issues associated with P0420. Mar 8, 2009 · I have an 02 celica gts p0420 code keeps coming back. I keep getting code p0420 and code p0010 when I scan my fusion, I replaced the cam shafts positioning sensor and the upstream 02 sensor and cleared the codes but when I drive the car then stop and start it again the codes come right back, don't know what I'm over looking, any ideas? Jul 22, 2018 · The most common fix for P0420 in the Chevy Cruze is a new catalytic converter, followed by an O2 sensor replacement. Dec 12, 2013 · So last February I had the Check Engine light come on my 2007 2. what are the symptoms of the p0420 code? The first and most typical P0420 code symptom is the check engine light coming on. May 12, 2018 · Following up - it's been about 2 years with this aftermarket cat (and P0420 code). Before taking your Forester into an exhaust shop for an (expensive) new catalytic converter, let’s ensure that’s what you need. May 13, 2023 · Started having issues months ago when my 2010 Subaru Forester (133K miles) threw the P2096 code. I've read where lots of people have gotten a new car but it didnt solve the problem. Connect the scanner and ignite your engine. 2023 Traverse LT 3. #8 · Dec 17, 2020. Please consider creating a new thread. 3 months later, the same code comes up. New NGK Iridium plugs air filter at 135k. I reset the codes, but w/in 5 miles, the codes came back. P0420 trips when the sensors are reading functionally but the system isnt seeing the nox reduction its expecting. Feb 4, 2024 · Myth: P0420 means you need a new catalytic converter. A failing oxygen sensor or bad catalytic converter are the most common causes of P0420. reddit. May 12, 2023 · The code states P0420 indicating the passenger side catalytic converter has failed. After the replacement I drove the car for about 7 miles before the engine light came on (p0420- Catalyst System Efficiency Below Jan 17, 2023 · When the efficiency of the catalyst system is below the threshold (Bank 1), the check engine light will come on with the trouble code P0420. Document all the codes, not just P0420. Automotive Mechanic. I had some questions about that one. 5L. Then you'll know if it's the downstream sensor or not or a ruined cat converter. Jun 26, 2021 · P0420 CEL. This code is caused by the oxygen sensor on the upstream side of the catalytic converter. The P0420 appears in the pending list after 5 minutes of driving. Table Sep 13, 2018 · This page is meant to help you troubleshoot the Ford Fiesta P0420 trouble code. Like. Feb 26, 2021 · In today's video we take a look at this 2014 Chevrolet Cruze with a 1. Why Does the P0420 Code Keep Coming Back? If you spend $900 or more to replace the catalytic converter, you may discover the check engine light coming on again later. I replaced the downstream O2 sensor, reset the computer, and went for a test drive. Model: N/A. After about 60 miles it made an "angry cat" sound for a few seconds then CEL comes back on. I tried Cataclean and it made the code go away for about a tank of gas. Replacing the o2 in that event would be pointless. If your Silverado’s computer doesn’t know the engine temperature, it’ll keep the fuel mixture rich. And if it's a ruined cat converter Step 2: Initiating the Diagnosis. As others have pointed out, that code doesn’t necessarily mean the cat is failing, replace it. Check Details Apr 26, 2021 · 08 v6/6. When this happens, the exhaust the O2 sensors see will be out of range, and it could throw P0420. Freeze Frame data is inconclusive, shows code set at 700 RPM, fully warmed up, off-idle throttle. I've put about three hundred miles on since then and just got a new code, P2097. 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. even though the check engine light alternates bet … read more Apr 9, 2012 · Try disconnecting your battery terminal for 30min, that will usually reset the codes. The dreaded p0420 keeps showing up after roughly 20 miles. 85@ 68 deg. The classic issue where the cell of the cat cuts the original o2 sensor in half. Jun 18, 2018 · 2014 Limited. I’ll recheck the exhaust for leaks beforehand. Please help! I replaced the upstream O2 sensor, reset the computer, and went for a test drive. Cylinder misfires will significantly reduce . I dropped it off with my mechanic again. I found a lot of information on checking the O2 sensors and performed the following tests. The code kept coming back and he decided to replace the catalytic converter. 5 Limited: Keep getting P0420 and P0430 codes. It signifies that the catalytic converter Feb 18, 2021 · Hi I got the dreaded p0420 code, 2012 cruze lt. Same code. #10 · May 5, 2016. Today my check engine light came back on. Also replaced the coolant temperature sensor. The code P0420 can be caused by the catalyst, O2 sensors before and after the catalyst. Find the OBD2 port, typically located under the dashboard. i . It turned off the service engine code for about 400 miles. Check for Other Codes. The scanner will start reading the codes. That means the operational efficiency of the catalytic converter is below its threshold. That is why you see the P0420 code. It threw a P0420 code a couple weeks ago so I had someone change the cat and both o2 sensors. #1 · Dec 11, 2019. Check for any exhaust leaks and repair. The function of the catalytic converter is to break down harmful gases created by a gasoline engine. The truck only have 45000 miles . Second, you might not be able to go faster than 30 to 40 mph since your engine won’t run as smoothly as it typically does. Had to cut my harness for it. This lasted a week or so. The scan tool P0420 - Catalyst System Low Efficiency. Feb 16, 2014 · 2007 Suzuki Sx4 crossover auto 137k. The first step is to check the engine light to see if the P0420 code is illuminated. I suggest you have a mechanic like one from YourMechanic do a complete diagnostics of the code Feb 5, 2008 · Re: P0420 Bank 1 Effic Below Threshold code keeps coming upCat or 02 or ?? (Jesse Treg) I have had the P0420 as well asp0102/p0113/91142. O2 Sensor Codes. P0420 code for over a year now, replaced both upstream and downstream O2 sensors and replaced the catalytic converter (OEM) and check engine light with this code keeps coming on. Here’s a good P0420 diagnostic order for the Subaru Forester: 1. Dec 2, 2015 · Another update, P0420 kept coming back regularly even after the temperatures warmed up. Before taking your Ram into an exhaust shop for an (expensive) new catalytic converter, let’s ensure that’s what you need. Last Time I Checked, That Particular DTC (Diagnostic Trouble Code) Was The Most Commonly Occurring Code Found On Vehicles With Illuminating CELs (Check Engine Light). Apr 16, 2018 · The CEL keeps coming back, always P0420 and only that code. Since the beginning I've had intermittent issues with cold starts and the idle is almost always too low at a stop. Three types of codes can give clues as to what’s going on with your truck. Feb 25, 2017 · About a year after having small problems, a larger problem popped up. So if it fluctuates too much, as the upstream sensor properly does, it suggests a problem with the cat. How can you fix the p0420 Nov 30, 2018 · The most common fix for P0420 in the Subaru Forester is a new catalytic converter, followed by an O2 sensor replacement. Diagnostics for this fault are abysmal. Mar 1, 2024 · A P0420 code on your Toyota Yaris isn’t serious but shouldn’t be ignored either because letting it linger for some time will harm the engine. #1. After about 25 miles of driving light came back on. Misfire Codes. 1 KB Views: 40. Hey guys, read lots of the forum but couldn't find what I needed. Table of Contents Credit: www. Mar 14, 2024 · The most common cause of the P0420 engine code is a degraded catalyst. 6L with p0420 code. It covers the P0420 code’s meaning, symptoms, causes, and possible solutions. - Rear … Dec 12, 2019 · Or you can wait for the problem to come and find you, rather than trying to find it. If both O2 sensors and catalyst was replaced then you may have an exhaust leak at the manifold or pipes. Obviously the catalyst is underperformingconsidering it isn't there. V. The causes of the P0420 code are a bad catalytic converter, an ECM update, an exhaust If code P0420 shows up on an OBD code reader, it means the engine’s harmful gasses production has increased. Sep 5, 2019 · What the code is telling you is that the catalytic converter has failed an efficiency test. A P0420 is set when the rear oxygen sensor voltage starts to oscillate at a greater frequency in both time and voltage. Dec 10, 2021 · How to tackle these DTCs. 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 May 10, 2023 · Conclusion. 6L 193,000. A week ago the engine light came on in my 2011 6spd Eco Cruze. P0420 Chevy Equinox Issue and Solutions to Fix Properly - UNCRD LAC P0420 Chevy Equinox Issue and Solutions to Fix Properly - UNCRD LAC. February 5, 2024. I see this all the time. Dec 11, 2019 · Cruze219 Discussion starter. 6L 125,000. P0423 – “Heated Nov 28, 2020 · 15990 posts · Joined 2015. When tackling these DTCs, you must first determine if the converter has truly failed or not. When I scan the code it says P0420 Catalyst system Efficiency Below threshold ” (Bank One). So to start off, I replaced my catalytic converters, between the radiator and firewall, in October of 2021 and since then I have been having P0430 and P0420 codes coming back repeatedly. On a PROPERLY running engine there are only 3 things that can cause this, faulty O2 sensors, defective cats or a wiring issue. Took it back to Firestone, and they replaced the O2 Sensors. The P0420 engine code indicates the catalyst system efficiency is below the 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. Last winter I had a thermostat stuck open on my 1998 Camry 2. I. The CEL just keeps coming back with the same Dec 23, 2020 · I have a 2015 Malibu 2. I have 2011 Enclave brought to mechanic yesterday. Jul 29, 2023 · 1999 Honda Civic EX 1. 4l p0420 keeps coming back. Jun 15, 2016 · If the ECU doesn't see the proper changes in the exhaust, eventually it will set the Check Engine Light with a code of P0420. Got the work done and got it back. Aug 24, 2022 · I have tried the following to resolve the P0420 code and it still won't go away: changed both Pre and Post Cat O2 sensors (ACDelco 213-3541 and 213-4191) Changed spark plugs (ACDelco 41-103) Changed MAF sensor (ACDelco 213-4222) Changed the oil with Mobil 1 (5w-30 high milage) Changed the oil filler cap (ACDelco FC219) P0420 That just keeps coming back. P0422 – “Main Catalyst Efficiency Below Threshold (Bank 1)”. What c … read more Jan 14, 2023 · You may find that doing the belt and spark plugs fixes all other issues, but if the catalyst codes persist, P0420 (bank 1) and/or 430 (bank 2) mean catalytic converter efficiency is below threshold. Here are some steps to fix a P0420 code Honda Accord. Replace sensor, suddenly the dreaded 420. Replaced both o2 sensors, have reset code several times and it keeps coming back. Vehicle: 2002 Prius. And finally at last, the pcm was reflashed. They didn’t keep up their end of the agreement. MIL came on around 6 weeks ago with a P0420 code. I guess the 'original' sensor was a dummy sensor. When I picked up my car he told me I had to drive the car for about 100 miles and then give inspection with the hope that fixed the P0420 code. ”. I have a 2014 Cruze LTZ with 131k miles. The oxygen sensor measures the oxygen levels in the exhaust system and reports back to the engine control unit. 4l 4 cylinder turbo engine. The P0420 generally means the downstream (post-cat) O2 sensor is not reading properly. Slow acceleration or inability to increase speed over 30-40mph. If ok, then you will need to replace the converter that bolts to the right side exhaust manifold (the one facing the rear of the Feb 28, 2021 · The CEL keeps coming back on with P0420 even with the new cats. Im a tech who works at a dealership. Tried cataclean and 'guaranteed to pass', worked last year before cat swap, but not this year. That sensor should be pretty steady when the cat is doing its job. Frequently Asked Questions Of P0420 Code Keeps Coming Back . This is an older thread, you may not receive a response, and could be reviving an old thread. Replaced with used OEM cat and Denso 234-4353 sensor. If the P0420 keeps coming back, it’s not fixed. What Does The P0420 Code Indicate? The P0420 code usually indicates a problem with the catalytic converter or the oxygen sensor. the S2s (after CATs) values are stable and less active. By using fine platinum and gold meshes to filter exhaust Aug 4, 2011 · About a month ago, I noticed CEL light coming on at the start of a long trip. This could be for one of two reasons: The catalytic converter performance, as measured by your O2 sensors, is not what it should be. I have a 2004 ranger with a 3. The one by the engine is easy to get to and replace. Dec 2, 2023 · The first time it was on a 6 cylinder vehicle that had 4 sensors. This “Catalyst system efficiency below threshold” code is triggered when your car’s computer (the powertrain or engine control module (PCM or ECM)) detects a catalytic converter issue. A P0420 code indicates a problem with the catalytic converter, more specifically. Once any other codes have been addressed, the next step is to inspect the exhaust system for any leaks or blockages. The Catalytic Converter is part of the exhaust that breaks down harmful May 11, 2017 · So my wife and I bought an '07 Outback Basic back in January, used with about 130k miles on it. While being one of the most common codes, it can also be one of the most inaccurate. Current LTFT +9%, STFT +/- 3%. Replaced rear cat, a year ago and nothing. 59. I have spent a week or so throwing a P0420 code, keeps coming back. Last week I replaced the firewall catalytic converter with a Magnaflow part #49446. Dec 26, 2018 · 420 code, keeps coming back. The first thing you want to do when trying to fix P0420 in the Tundra is to verify there aren’t any other trouble codes. I suggest you change both out. P0420 is the most common OBDII code and is virtually never a breakdown risk. Bought this car 3 years ago. Myth: Resetting P0420 is just as good as repairing it. Jump to Latest Follow Before the sensor 'fell off,' was there a code p0420? Attachments. There are two of them, one before and one after the catalytic converter. 2010 Traverse 3. Reset the code and then continue driving. 1999CamrySFI27n62. Remember, interlinked issues like misfire or oxygen sensor codes might be crucial. I reset the code and drove the car for about 10,000-15,000 miles no problems. Feb 5, 2024 · The catalytic converter is one of them. The most common codes that people will see in this particular situation are P0134, 0138, and 0139, though you are probably seeing P0420. The car had 65k on it at that point. For most people, the first sign that anything is wrong is the service engine soon light coming on. Fact: While the converter is often the root issue, you may need new oxygen sensors or exhaust repairs. 2014 3. Nov 30, 2023 · P0420 Causes and Common Fixes. P0420 Chevy Equinox Issue and Solutions to Fix Properly - UNCRD LAC P0420 chevy code gmc chevrolet buick engine light Image2 jpeg chevy. Based on that, I think replacing the cat was right but I have a slight exhaust leak somewhere. Nov 25, 2022 · In some cases, the P0420 Chevy Equinox trouble code could be caused by a number of other issues. Jan 29, 2024 · The P0420 code is a common diagnostic trouble code that indicates an issue with the catalytic converter in a Subaru Forester. If the engine light is on, then the next step is to check for any other codes that may be accompanying the P0420 code. I kept driving, and after 2000 miles, 8 gas tanks later, I got home, plugged in the Actron reader, and it read 10 codes. I stopped at an AutoZone and they read the code P0420. P0420 code comes back almost immediately after clearing instead of after 20-50 miles. I took it to my mechanic and they confirmed my fear. The exhaust smells very strongly too. The P0420 Diagnostic Trouble Code is a clear indication that your vehicle's catalytic converter is not efficiently functioning. That threshold is 97%. Jun 15, 2023 · The P0420 code can occur if there’s a problem with the oxygen sensor. I had the same code and it turned out to be the cat but you'll want to make sure its not an O2. The purpose of the catalytic converter is to break down harmful pollutants created during the combustion cycle. The two oxygen sensors have measured its efficiency and deemed that it is low. 6L 24,000. Mechanic said he checked for leaks before replacing cat, I asked to check the manifold also, he said he checked it all. A new catalytic converter starts out at close to 99% efficiency and quickly tapers off to around 95% efficient. May 24, 2023 · 1. PCM judges this by what the 4 O2s are reporting. I replaced all oxygen sensors and the still is coming back after 2-3 drive cycles. First, remove the O2 sensor and pour 4-6 ounces of seafoam into the opening, replace the sensor, and leave it overnight. I have replaced upper and down stream 02 sensor on bank 2. It covers the P0420 code's meaning, symptoms, causes, and possible solutions. If they installed an aftermarket (non General Motors) converter, that could be the issue. Possibly the O2 sensor. Check Details. I am getting codes P0420 and P0430. Jan 7, 2024 · Chevy p0420 c10 liter keeps answers coming any Equinox cargurus problems 2012 chevrolet equinox 135,000miles 2. Sulfurous smell from the exhaust pipe. Tried to disconnect the battery. I had some misfiring when my spark plugs went bad around 100k miles, and I replaced them about 5k miles ago. " I took it to a non-GM service center, and the … read more. The engine’s power output has decreased, which is the cause of this. Then I got a P0422 which was the other sensor on the same side. I'll try one or two other data points on Torque for air fuel and 02 sensor1 equivalence to see if any readings at all. The other is DIY too, once you get under the car. The P0420 code is a generic diagnostic trouble code that indicates a problem with the catalytic converter's efficiency in the exhaust system. Just got my scorpion catless downpipe installed, have about 1000km on it. I changed the one sensor kicking out the code (P0421 I think). You'll be surprised at how many P0420/P0430 codes are corrected without replacing the cat! If the converter has failed, you also need to identify what caused the converter to fail. 2013 Equinox 3. 2l p0420 code. Sep 20, 2018 · This page is meant to help you troubleshoot the Honda CR-V P0420 trouble code. He suggested cleaning the manifold before deciding to get new catalytic converter. Drove over something in road and damaged o2 sensor, replaced with another and all was well. I have been dealing with this intermittent issue for 3 years. You should see P0128 along with this code. This code is significant as it can affect the vehicle’s emissions and overall performance. The S1s (front) as seen with a OBD-II scanner should bounce around at lot where. I cleared the code yesterday drove it around and after 20 miles it made that angry cat sound again and the CEL came back on. #2 · Apr 27, 2021. However, if the P0420 code keeps coming back, then we recommend you visit a Toyota dealership. pdf. Here’s a good P0420 diagnostic order for the Dodge Ram: 1. Almost always cats in my experience. Bank 1 refers to the side of the engine that houses the number one cylinder. Now receiving an active code C1623 and P0106. This lasted another few days. 4 4 cylinder Accord. both o2 sensors and the cat have been changed highflow magnaflow 3 way cat installedwhat else could trigger this code Submitted: 15 years ago. New cat converter, new acdelco o2 sensors, new injectors, new high fuel pressure pump, new intake manifold and and all gaskets. Lastly, the vehicle may have exhaust leaks, and the oxygen sensor will be inoperable. Again, around 3-4 months later, the same code arises. So I am not sure what else to try. These codes do not point out to a specific issue but they can help hint at the root cause of the issue. When the upstream and downstream oxygen sensors have identical readings, the catalytic converter is not doing its job Jul 7, 2021 · Top 4 Reasons Why You Replaced O2 Sensor and Still Have Code. I’m currently thinking the first aftermarket cat I bought is not efficient enough and am wanting to returning it to buy an OEM one. The most common reason why fault code P0420 comes up is a problem with the catalytic converter. Jan 24, 2023 · 2009 GMC Acadia P0430 & P0420 keep coming back. Aug 30, 2020 · I still have P0420. The ECM tests the catalytic converter to gauge its efficiency when certain conditions are met. Some mechanics will tell you to try replacing the oxygen sensors first, to see if that solves the problem. A P0420 code is a trouble code on OBD-II equipped vehicles. All vehicles from 1996-newer sold in North America support this generic powertrain code. Here’s a good P0420 diagnostic order for the Chevy Cruze: 1. I just relaxed the third converter after the y-pipe this past Mar 12, 2021 · Now, we’ve established that DTC P0420 is caused by a bad signal from your O2 sensors. Jan 11, 2016 · P0420 Code. Jun 23, 2022 · Check Engine Light and P0420 and P0430 Codes. Nov 15, 2008 · 2001 Tacoma 4wd 2. Feb 17, 2019 · P0420 code. I have no exhaust leaks that I’m aware of. I had the po420 code so I changed the catalytic converter with a Magnaflow converter and both O2 sensors with Bosch sensors. Oct 12, 2018 · Here’s a good P0420 diagnostic order for the Toyota Tundra: 1. I know the p0299 is probably a bad turbo. Problem: MIL Lamp on (P0420) Diagnosing: The technician tried to clean the fuel injectors because of found a clogged fuel filter and replace the front O2 sensor because he found the data unusual. I started replacing things one at a time, solving the P2096 code, but now I have the P0420 that keeps coming back. Not much longer. 16 years of experience. If your car's check engine light is on, get that code read in case it's a P0420. Fact: The underlying cause must be diagnosed and repaired properly, or the code will return. The check engine light is on and it has a P0420 code stored Oct 20, 2023 · Usually, when you have a code P0420, the check engine light will come on, and your vehicle may remain completely drivable. Dec 15, 2008 · The P0420 DTC could be the cat, O2 sensor 1 or O2 sensor 2. Have run cat cleaner and seafoam through it. Perhaps your catalytic converter is failing, or "poisoned" from chemicals that were not supposed to be in the exhaust. 0420-Bank 1: Efficiency Below Threshold 0102-MAF circuit low input 0113-Intake Air Temperature (IAT) Sensor 1 Circuit (G42): High Input 1142-Load calculation cross check: lower limit exceeded Aug 25, 2023 · The computer goes through a number of checks/monitors and then sets the code and turns the engine light on, even though the fuel system/converter problems may be present as soon as you start the engine. Took it to Firestone and had the Catalytic Converter replaced for a not so fun charge. 8L eng code p0420 keeps coming back cat hasben changed twice & post cat o2 sensor hasbe changed - Answered by a verified Buick Mechanic We use cookies to give you the best possible experience on our website. Jul 26, 2018 · Engine Temp Sensor Codes. One thing to keep in mind is that a bad oxygen sensor will not cause the fuel injection computer to set a P0420 trouble code, although a failing O2 sensor can contribute to the failure of the catalytic converter. com . However, these symptoms may also appear: Loss of power, even after warming your vehicle up. Replacing the oxygen sensors, before they throw a code can save a catalyitc converter. However, most modern cars have two oxygen sensors – one before the catalytic converter, and one post-cat sensor. The second cat after the rear oxygen sensor I also replaced. Have airbag light on (inactive codes B1481,C1611, B1492, B2500). You said you had the complete exhaust system replaced. One is behind or beside the engine, the other near the catalyic converter. I have a 2014 Cruze LTZ which is showing a P0420 code "Catalyst System low Efficiency. i. Then the codes were pointing to the other side's exhaust so I just replaced both and the problem Jay Safford. The P0420 code in a Honda Pilot will often be thrown if one of your vehicle’s oxygen sensors is not functioning correctly. One or both of your O2 sensors is faulty, either because of an electrical fault or because the sensor probe is choked up with Nov 12, 2023 · Hello. Suppose you suspect your Honda car has this code. tn ot ob qv rj bu ll tv td ji