Code p0420 chevy

1. Chevrolet. If you experience a P0420 code in your Chevy, it is often due to an exhaust leak before the catalyst. It can also be caused by a faulty downstream oxygen sensor (rear) or a faulty catalytic converter.

Code p0420 chevy. Mar 2, 2022 · I keep getting a check engine light code for P0420 Catalyst System Efficiency Below Threshold (Bank 1) on a 2016 Chevy Trax. I change both O2 sensors out and even the Catalytic convert. I went with Certified GM parts to replace the bad parts with. I can reset the code but it comes back with in a day or so.

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 ...

Now I keep getting P0420 codes. I see that P0420 is Catalyst System Efficiency Below Threshold and "A code P0420 may mean that one or more of the following has happened": ... engine in my 2000 S10 (I know a guy at the Chevy dealer who owed me a favor) along with new injectors and fuel pressure regulator (Sorenson).o2 sensors )AC …This page is meant to help you troubleshoot the Chevy Suburban P0430 trouble code. It covers the P0430 code's meaning, symptoms, causes, and possible solutions. P0430 is an emissions-related trouble code and is virtually never a breakdown risk. ... The bank 1 version of this code is P0420. Chevy Suburban P0430: Symptoms.Sep 21, 2023 · In this blog post, we'll delve into the P0420 code, explore what it means, and discuss its significance for various car makes, including Honda, Ford, Chevy, and Nissan. Understanding the P0420 Code The P0420 code is a generic OBD-II (On-Board Diagnostics) code that is uniform across various car manufacturers. The P0420 code in a Chevy Malibu will often be thrown if one of your car’s oxygen sensors is not functioning correctly. There are rarely drivability issues associated with P0420. For most people, the first sign that anything is wrong is the service engine soon light coming on.Oct 8, 2022 ... The code P0420 - Catalyst Efficiency Below Threshold (Bank 1) means that there is a problem with the catalytic converter of the Bank 1.aalcala Discussion starter. 5 posts · Joined 2013. #1 · May 20, 2013. My check engine light came on and is reading a a code P0420. This code reads Catalyst System Efficiency Below Treshold (Bank 1) Decided to check into it and it seems I have a cracked exhaust manifold. My car has bout 95,000 miles on it.Mar 14, 2024 · The most common cause of the P0420 engine code is a degraded catalyst. Catalytic converters/catalysts break down over time and can also become clogged. Cylinder misfires will significantly reduce ... The code P0420 - Catalyst Efficiency Below Threshold (Bank 1) means that there is a problem with the catalytic converter of the Bank 1. The code P0430 means the same fault for the Bank 2 catalytic …

P0420. I just had that same code, mine was trying regen and only get to 700F - Replaced the 9th injector, regen completed @1400f in 30 mins first time i started the truck, a week ago and no more code. 2013 Chevy 2500HD LTZ 4wd 102k miles Stock as far as i know. Bought used with 88k in 2018, all emissions are intact.Code Number Code Description Related Codes; P0420: Catalyst System Efficiency Below Threshold (Bank 1) P0430 - Catalyst System Efficiency Below Threshold (Bank 2)Regardless, P0420 is related to HC (hydrocarbon (diesel)) conversion rate not a DEF problem. As wiilydmax indicated, there is likely some problem with the 9th injector (regen injector) not spraying correctly, so the fuel isn't being converted to enough heat to get the regen done. 2023 LZO CC std box 4x4.EPA Standard: This three-way catalytic converter complies with EPA standard and OBD2 standard, and can solve the P0420 code thrown by the engine. This ...Today, it has 171,424 miles. P0420 has thrown other codes which disappeared when I did the work listed below. 1. Installed new spark plugs (ACDelco 41-109 Iridium Spark Plugs) 19.99. 2. Installed new ignition coils (D515 Ignition Coil ACDelco C1555) 205.27. 3. Installed new Camshaft Position Sensor (OEM Engine Camshaft Position Sensor 12615371 ...Chevrolet P0420 Trouble Code. The Chevy Cobalt, Malibu, Equinox, and Silverado pickups are prone to P0420. On these vehicles, trouble accelerating and reduced MPG accompany the code. Upstream oxygen sensors need frequent replacement. Eventually, the cat also requires replacement after 5-7 years of use.

Chevy Camaro P0420 Code Symptoms. The P0420 code in a Chevy Camaro will often be thrown if one of your car’s oxygen sensors is not functioning correctly. There are rarely drivability issues associated with P0420. For most people, the first sign that anything is wrong is the service engine soon light coming on. How to fix a Chevrolet P0420 engine code: Catalyst System Low Efficiency Bank 1Link to Cataclean on Amazon: https://amzn.to/3TSI6xWHow To Test Oxygen Sensor ... The P0420 code signals a low catalyst system efficiency. This code suggests that the oxygen levels are below the desired threshold (Bank 1), which most often results from problems with your car’s exhaust or fuel systems. It can sometimes be tricky to diagnose. The catalytic converter is a component of the vehicle’s exhaust system.Aug 12, 2009 ... Typically the P0420 code triggers the Check Engine Light if the readings of the two sensors are similar. This is indicative of (among other ...If the code changes to P0420, that would indicate that one of the O2 sensors is bad on the bank 2 side. Conclusion If there are no codes other than P0430 present, and the O2 sensors are recording data properly, it’s likely your Chevy Suburban’s catalytic converter has failed, which is what this code is reporting.P0420 is a cat efficiency code - so probably the post cat sensor since it monitors the cat just like on our cars. Sure it's the 02 and not the cat? jigger1166's ...

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The P0420 code indicates that your vehicle’s powertrain control module (PCM) monitors the poor efficiency of the catalytic converter at Bank 1. This code may also be triggered due to a bad catalyst or a false alarm caused by a faulty oxygen sensor at Bank 1. Basically, Bank 1 and Bank 2 are the two sides of the engine.The most common reason why fault code P0420 comes up is a problem with the catalytic converter.The function of the catalytic converter is to break down harmful gases created by a gasoline engine. When the upstream and downstream oxygen sensors have identical readings, the catalytic converter is not doing its job of reducing harmful …215 posts · Joined 2013. #3 · Jul 22, 2017 (Edited) I believe P0420 can really only be due to bad O2 sensors, wiring to said sensors, or the catalytic converter getting plugged up - especially if it's the only code. If I remember correctly, P0420 is caused by the computer seeing a data difference between the pre-cat and post-cat oxygen ...The P0420 code in a Chevy Impala will often be thrown if one of your car’s oxygen sensors is not functioning correctly. There are rarely drivability issues associated with P0420. For most people, the first sign that anything is wrong is the service engine soon light coming on.Chevy. Chevrolet cars can encounter the P0420 code due to similar reasons as other manufacturers. Regular inspections and timely replacements of catalytic converters and oxygen sensors can keep your Chevy running smoothly. Nissan. Nissan vehicles may exhibit the P0420 code due to catalyst inefficiency.January 2, 2023 by Jason. This page is meant to help you troubleshoot the Chevy Equinox P0420 trouble code. It covers the P0420 code’s meaning, symptoms, …

A P0420 code is set when the upstream sensor and the downstream oxygen sensor sense the catalytic converter is not doing its job. Basically, the amount of oxygen going into the converter is not being burned, and it detects it through the downstream sensor. Oxygen is the key here. Modern Engine Management Systems …Jan 24, 2023 · To further clarify, from my own experience with p0420, the "catalyst efficiency" can be made to increase and exceed the threshold by which the p0420 code is set by correcting the engine issues. When monitoring my engine using Torque Pro ($5.00) and an OBD2 bluetooth adaptor ($35.00), I can track the pid "catalyst efficiency" in the "test ... The causes of the P0420 code are a bad catalytic converter, an ECM update, an exhaust... In this video, you'll learn the causes and solutions of the P0420 code.Code P0420. Jump to Latest Follow ... I have a 2015 Chevy Cruze with the 1.4L turbo. I’ve been having issues for sometime now regarding that P0420 code but I’ve already replaced the cat and the O2 sensor on it. I haven’t changed the downstream sensor tho. Would you recommend to change the downstream sensor as well or would that not …Chevy / GMC Duramax 11-16 LML Forums. 11-16 LML Duramax Powertrain P0420. Jump to Latest ... I’ve had this code in the past, cleared it and a month later it was back. ... DTC P0420 Diagnostic Instructions. Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.In this video, you'll learn the causes and solutions of the P0420 code. The causes of the P0420 code are a bad catalytic converter, an ECM update, an exhaust...Oct 8, 2022 ... The code P0420 - Catalyst Efficiency Below Threshold (Bank 1) means that there is a problem with the catalytic converter of the Bank 1.If you’re a car owner, there’s a good chance that at some point you’ve encountered the dreaded check engine light. Code P0420 is a generic diagnostic trouble code that indicates an...#1 · Mar 23, 2021. Ever heard of this code? well I got hit with it a while back and it has been coming and going for sometime. Some details about my traverse.. 2010 LT AWD, …This page is meant to help you troubleshoot the Chevy Equinox P0430 trouble code. It covers the P0430 code's meaning, symptoms, causes, and possible solutions. P0430 is an emissions-related trouble code and is virtually never a breakdown risk. ... If the code changes to P0420, that would indicate that one of the O2 sensors is …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. The engine coolant temperature sensor is not working properly.The forthcoming Chevy Bolt and expected improvements in the Nissan Leaf will provide electric car owners with greatly increased driving range at affordable prices. By clicking "TRY...

The most common fix for P0420 in the Chevy Cruze is a new catalytic converter, followed by an O2 sensor replacement. Before taking your Cruze 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 Chevy Cruze: 1. Check for Other Codes.

May 6, 2024 ... I have had the catalytic converter changed and sensors along with a gasket. Still code pops up. Why?Regardless, P0420 is related to HC (hydrocarbon (diesel)) conversion rate not a DEF problem. As wiilydmax indicated, there is likely some problem with the 9th injector (regen injector) not spraying correctly, so the fuel isn't being converted to enough heat to get the regen done. 2023 LZO CC std box 4x4.2014 Cruze P0420 and P0171 thrown at same time. HI I have a 2014 I4 turbo with lil over 92K miles on it. For the longest time I have had a P0420 code on it . I replaced the front O2 sensor and code cleared for a a couple of days and then it came on again. I had a smoke test done to get the true diagnostic issue and said needed to replace the ...Jul 27, 2018 · The P0420 code in a Chevy Malibu will often be thrown if one of your car’s oxygen sensors is not functioning correctly. There are rarely drivability issues associated with P0420. For most people, the first sign that anything is wrong is the service engine soon light coming on. Typically the P0420 code triggers the Check Engine Light if the readings of the two sensors are similar. Oxygen sensors are also referred to as ...If the code changes to P0420, that would indicate that one of the O2 sensors is bad on the bank 2 side. Conclusion If there are no codes other than P0430 present, and the O2 sensors are recording data properly, it’s likely your Chevy Suburban’s catalytic converter has failed, which is what this code is reporting.Codes: (MOST CURRENT CODES AS OF RIGHT NOW) P2097: Post catalytic converter fuel trim (FT) bank 1- too rich. P0420: Catalytic converter system, bank 1 -efficiency below threshold. Exact Chevy Diagnosis: CAUSE: ENG replaced valve cover, customer declined spark plugs, advised converter may have been damaged also.Feb 15, 2020 · WHAT CAUSES CODE P0420 ENGINE LIGHT CHEVROLET, CHEVY, GMC, BUICK, CADILLAC Great Car Scanner: https://amzn.to/2QmNBri Check out our Amazon Store for the to... Jun 13, 2022 ... In my case it was a false code reading. usually this means an exhaust leak, but you said they already found a leak... so... Maybe it's another ...=====Claim your FREE engine code eraser 👉 https://free.nonda.co 👈== How to Fix P0420 =====Engine Code P0420 Saving Repair Part...

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2014 Need help: codes P0420 & P2097. Hi all. Hoping to get some help and avoid multiple costly trips to the dealership for service. My wife’s 2014 Volt started smoking from the exhaust last week on her way home from work and the check engine light came on. The communication center read “propulsion power is reduced “ and “engine not ...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. The engine coolant temperature sensor is not working properly. How to fix a Chevrolet P0420 engine code: Catalyst System Low Efficiency Bank 1Link to Cataclean on Amazon: https://amzn.to/3TSI6xWHow To Test Oxygen Sensor ... 1604 posts · Joined 2010. #2 · Jul 30, 2010. P0420 is a catalyst efficiency code. 100% of the time you need a new catalytic converter. If you want to be sure it is the cat pull the O2 sensor before the cat and drive it, the sluggishness will go away because there is no more restriction. Depending on you mileage you may be covered under the 8 ...GM may be replacing tens of thousands of Bolt EV batteries, but it won’t have to pick up the tab for most of them. The automaker has reached a deal that will have LG pay nearly all...Regardless, P0420 is related to HC (hydrocarbon (diesel)) conversion rate not a DEF problem. As wiilydmax indicated, there is likely some problem with the 9th injector (regen injector) not spraying correctly, so the fuel isn't being converted to enough heat to get the regen done. 2023 LZO CC std box 4x4.Interpreting the P0420 Code. If the O2 sensors detect similar results, then something is not right. The values of oxygen have to be different upstream and downstream from the converter. If not, the O2 sensor sends this information to the ECU, which signals the P0420 code. Common Symptoms of a P0420 CodeThe most common fix for P0420 in the Chevy Aveo is a new catalytic converter, followed by an O2 sensor replacement. Before taking your Aveo 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 Chevy Aveo: 1. Check for Other Codes.4 posts · Joined 2015. #36 · Nov 25, 2015. P0420 checks the health of the catalyst by injecting raw fuel into the catalyst and checking for a temperature rise on the EGT sensor downstream of the catalyst. It should only set if catalyst is melted (very rare), poisoned (possibly from oil), or plugged with soot. Share.Code P0420 Description. The Engine Control Module (ECM) uses sensors mounted in front of and behind the Three-Way Catalytic Converter (TWC) to monitor its efficiency. The first sensor, the air-fuel ratio sensor, sends pre-catalyst information to the ECM. The second sensor, the heated oxygen sensor, sends post-catalyst information to … ….

If you're experiencing problems with your car and see the P0420 code on your code scanner, don't worry. In this video, I'll show you the meaning of this trou...When the P0420 code appears, the catalyst system efficiency is below the threshold for a particular engine bank, often referred to as Bank 1. This code is related to the vehicle's catalytic converter and oxygen sensors. The primary purpose of a catalytic converter is to reduce harmful emissions from the engine by converting toxic gasses, …Feb 8, 2024 · 2014 Need help: codes P0420 & P2097. Hi all. Hoping to get some help and avoid multiple costly trips to the dealership for service. My wife’s 2014 Volt started smoking from the exhaust last week on her way home from work and the check engine light came on. The communication center read “propulsion power is reduced “ and “engine not ... As the code description implies the P0420 code means that the vehicle's control module has detected that the three-way catalytic converter is not working …This page is meant to help you troubleshoot the Chevy Suburban P0420 trouble code. It covers the P0420 code's meaning, symptoms, causes, and possible solutions. P0420 is the most common OBDII code and is virtually never a breakdown risk. A failing oxygen sensor or bad catalytic converter are the most common causes of P0420. TableP0420 Chevy Silverado GuideMechanic.Com – Causes Of P0420 Code – P0420 code is a common diagnostic trouble code that often appears in the performance of a vehicle. It indicates that there is an issue with the catalyst system’s efficiency, and the vehicle is not able to reduce the emissions as per the required.Chevy / GMC Duramax 11-16 LML Forums. 11-16 LML Duramax Powertrain P0420. Jump to Latest ... I’ve had this code in the past, cleared it and a month later it was back. ... DTC P0420 Diagnostic Instructions. Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.December 22, 2022 by Jason. This page is meant to help you troubleshoot the Chevy Blazer P0420 trouble code. It covers the P0420 code’s meaning, symptoms, …Chevy / GMC Duramax 11-16 LML Forums. 11-16 LML Duramax Powertrain P0420. Jump to Latest ... I’ve had this code in the past, cleared it and a month later it was back. ... DTC P0420 Diagnostic Instructions. Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.darkstarmoto. 344 posts · Joined 2012. #3 · May 10, 2017. P0420 is not indicative of a failed cat. It just means that the upstream and downstream sensors readings are not jiving. This could be a few things like an exhaust leak, a sensor that is failing (as noted in above post). Give this a read, may save you the cost of a new convertor. Code p0420 chevy, 215 posts · Joined 2013. #3 · Jul 22, 2017 (Edited) I believe P0420 can really only be due to bad O2 sensors, wiring to said sensors, or the catalytic converter getting plugged up - especially if it's the only code. If I remember correctly, P0420 is caused by the computer seeing a data difference between the pre-cat and post-cat oxygen ..., If the code changes to P0420, that would indicate that one of the O2 sensors is bad on the bank 2 side. Conclusion If there are no codes other than P0430 present, and the O2 sensors are recording data properly, it’s likely your Chevy Impala’s catalytic converter has failed, which is what this code is reporting., Jul 27, 2018 · The P0420 code in a Chevy Impala will often be thrown if one of your car’s oxygen sensors is not functioning correctly. There are rarely drivability issues associated with P0420. For most people, the first sign that anything is wrong is the service engine soon light coming on. , P0420 is probably the most common code seen. It refers to "Catalytic Converter Efficiency" Basically, it Engine Control Module (ECU) monitors the chemical constituents of the exhaust, both before and after the catalytic converter. ... (I also have a 2011 Chevy Equinox with this issue and just had my cat. conv. replaced because of it) …, The first thing you should do when you get a P0420 code is NOTHING. Check your warranty manual. Your emission control system may be warrantied for 15 years or 150,000 mi. If you do not have your manual, go to a Chevrolet Dealer. You do not have to be the original owner. The warranty is tied to your VIN number. I have a 2013 Cruze LS …, The 420/430 are saying Catalytic converter system, efficiency below threshold for both sides. PCM judges this by what the 4 O2s are reporting. The S1s (front) as seen with a OBD-II scanner should bounce around at lot where. the S2s (after CATs) values are stable and less active., Mar 14, 2024 · The most common cause of the P0420 engine code is a degraded catalyst. Catalytic converters/catalysts break down over time and can also become clogged. Cylinder misfires will significantly reduce ... , Aug 4, 2018 · Chevy Monte Carlo P0420 Code Symptoms. The P0420 code in a Chevy Monte Carlo will often be thrown if one of your car’s oxygen sensors is not functioning correctly. There are rarely drivability issues associated with P0420. For most people, the first sign that anything is wrong is the service engine soon light coming on. , Everything was running fine until about a couple of weeks ago when my car started throwing the P0420 code *Catalyst efficiency low bank 1*. I figured that since I had a new Cat. Converter, that it was more than likely my O2 sensor going bad (after the Cat). ... Chevy Silverado EV Forum 2K+ members. AT4X versions of the GMC Sierra and …, Causes. Diagnosis. Chevy Silverado P0420 Quick Info Table. Chevy Silverado P0420 OBDII Code Defined. P0420 is generic (has the same meaning for all …, Chevy Monte Carlo P0420 Code Symptoms. The P0420 code in a Chevy Monte Carlo will often be thrown if one of your car’s oxygen sensors is not functioning correctly. There are rarely drivability issues associated with P0420. For most people, the first sign that anything is wrong is the service engine soon light coming on., Jul 25, 2018 · Chevy Tahoe P0420 Code Symptoms. The P0420 code in a Chevy Tahoe will often be thrown if one of your vehicle’s oxygen sensors is not functioning correctly. There are rarely drivability issues associated with P0420. For most people, the first sign that anything is wrong is the service engine soon light coming on. , Jul 26, 2018 · The P0420 code in a Chevy Suburban will often be thrown if one of your vehicle’s oxygen sensors is not functioning correctly. There are rarely drivability issues associated with P0420. For most people, the first sign that anything is wrong is the service engine soon light coming on. , How To Fix The P0420 Trouble Code. Verify the code with an OBD-II scanner and reset the check engine light to see if it comes back. Inspect and replace faulty oxygen sensors. Check for exhaust leaks and repair as necessary. Replace worn-out spark plugs or spark plug wires., What Does Code P0420 Mean? OBD II fault code P0420 is a generic code that is defined as “Catalyst System Efficiency Below Threshold (Bank 1)”, and is set when the PCM (Powertrain Control Module) detects a condition that indicates that the catalytic converter on Bank 1 is operating below the minimum allowable efficiency threshold., My 2013 Chevy Equinox with the 2.4L is showing a P0420 code. The code first appeared a few weeks ago, turned itself off after a few days and then returned. I took it into a trusted shop and they recommended to start with replacing the 02 sensors. They wanted an arm and a leg to do the job so I replaced them myself using GM/AC Delco …, P0420 Engine Controls and Fuel Catalyst low efficiency. If it was one of the HO² sensors it would have set a specific code for that particular sensor. P0420 is very hard to diagnose. It could be as simple as a dirty air filter to a bad CAT. Never drive faster than your guardian angel can fly!!!, P0420 Code - Catalyst System Efficiency Below Threshold Bank 1. How to Fix. ... P0420 Chevrolet Catalyst System Low Efficiency Bank 1 ..., Oct 10, 2020 ... There is a lot of advice on this issue but in my case it appears to be a cracked flex pipe. Hoping this helps others diagnose their issue ..., Typically the P0420 code triggers the Check Engine Light if the readings of the two sensors are similar. Oxygen sensors are also referred to as ..., Dec 23, 2018 · Chevy Uplander P0420 OBDII Code Defined. P0420 is generic (has the same meaning for all vehicles made in 1996+) OBDII trouble code. Here’s the technical definition for your van: P0420: Catalyst System Efficiency Below Threshold (Bank 1) Catalyst System Efficiency. Your Uplander’s exhaust contains hydrocarbons, carbon monoxide, and other ... , The code P0420 on your 2016 Chevrolet Sonic LT indicates that the catalytic converter is not working properly. However, the fact that the converter is only a few months old makes it less likely to be the culprit. Here are some other things that could be causing the code:A bad oxygen sensor., Amelia J. on June 15, 2016. I took my car to the dealership to have it checked out. Two codes were found: PO420 and PO171. They told me that the P0420 is a problem with the actuator (part number 17230-21010), and the 2nd one has to do with the Mass Air Flow (22204-21010). Both of these makes my check engine light continually appear and they ..., Some check engine codes, including the P0420, can mean you have a leaky exhaust. Check for leaks before you go swapping parts. Finding the leak is easy and f..., A popular car modification is the stereo system. Replacing the stereo enables the car owner to add an aftermarket stereo with a number of features such as MP3 players, Bluetooth co..., It’s official: a fully electric Chevy Corvette is coming — with new battery technology to boost its range, acceleration and efficiency. When it arrives, the battery-electric sports..., Chevy Monte Carlo P0420 Code Symptoms. The P0420 code in a Chevy Monte Carlo will often be thrown if one of your car’s oxygen sensors is not functioning correctly. There are rarely drivability issues associated with P0420. For most people, the first sign that anything is wrong is the service engine soon light coming on., Step 1 – Resolve Engine Trouble Codes. The first step is to resolve any other codes that may have come up in addition to the P0420; especially troublesome is the P0300 series of cylinder misfire codes. A P0300 code could be related to something in the ignition (spark plug or coil), the fuel injector, compression or fuel contamination., Some check engine codes, including the P0420, can mean you have a leaky exhaust. Check for leaks before you go swapping parts. Finding the leak is easy and f..., Aug 4, 2018 · Chevy Monte Carlo P0420 Code Symptoms. The P0420 code in a Chevy Monte Carlo will often be thrown if one of your car’s oxygen sensors is not functioning correctly. There are rarely drivability issues associated with P0420. For most people, the first sign that anything is wrong is the service engine soon light coming on. , i had both p0420 and p0430 (triggered by P0069 code) codes before did not need to replace them that is why it's a good idea to check other things first..., Oct 21, 2020 ... To anyone with this error code, CHECK YOUR SPARK PLUGS! The previous owner never changed them and I was in the process of replacing them ..., Chevrolet cars can encounter the P0420 code due to similar reasons as other manufacturers. Regular inspections and timely replacements of catalytic converters and oxygen sensors can keep your Chevy running smoothly. Nissan. Nissan vehicles may exhibit the P0420 code due to catalyst inefficiency. Issues with the catalytic converter or …