Jeep p0420 code

I found fault code p0420 with my reader..catalytic..O2 sensors - Answered by a verified Jeep Mechanic. We use cookies to give you the best possible experience on our website. ... 2008 Jeep Wrangler codes p0430 and p0420. Need help diagnosing.

Jeep p0420 code. Causes. Diagnosis. Jeep Compass P0420 Quick Info Table. Jeep Compass P0420 OBDII Code Defined. P0420 is generic (has the same meaning for all vehicles …

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The Jeep runs fine really good actually. I don't care about looking at light just want it reliable . Save Share. Like. Sort by Oldest first Oldest first Newest first ... this will absolutely throw p0420 and related codes. I hope you are back up and running by now, if not i hope this helps! Black 2007 JKU Sahara, Rubicon Express 3.5" long arm ...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 leave a little bit of extra ...Dreaded P0420 Code -- after resolving misfire. Friends, I'm getting the P0420 code, Catalyst System Efficiency Below Threshold (Bank 1). Long story short, I drove several hundred miles with a misfire caused by a gunky fuel injector in cylinder 1 (codes: P0301, P0201). Hated to keep driving on it, but I was far from home when the misfire started ...El código P0420 se refiere a un problema con el sistema de control de emisiones de tu vehículo, específicamente al convertidor catalítico. Este componente es crucial para reducir las emisiones dañinas de escape y garantizar que tu automóvil cumpla con los estándares de emisiones. Cuando se activa el P0420, generalmente indica que el ...Jeep wrangler p0456: evap system - small leak Jeep wrangler How to fix trouble code p0339 for jeep jk unlimited rubicon 3.6l Jeep wrangler p0304: cylinder 4. ... Jeep Wrangler Jk P0420 Code. Jeep wrangler jk iii rubicon road off autodata1 Wrangler jeep jk 2007 overland build drivingline trail Wrangler p0456 evap obdii.

12 posts · Joined 2022. #1 · Feb 27, 2022. I have a 2008 Jeep Liberty 4x4 Sport V6. I'm getting a P0420 catalytic efficiency below threshold Bank 1 code. The shop has already changed one broken valve spring and 3 fuel injectors. After this last visit to the shop, replacing the last two fuel injectors made a huge difference.Just bought a 2008 Jeep Patriot Limited. It is the first Jeep I have owned and am pretty happy with it. I bought it with 170,000km on it, and it has the check engine light registering code P0420 (catalytic converter issue). I am going to try two things: First, I am going to replace the O2 sensors. Second, I was thinking of trying to clean the ...It also could be that the engine coolant temperature sensor isn't working properly, but I think if that was the issue it would throw a separate code. Code P0420 is catalyst efficiency bank 1 (passenger side). You can check on-line how to test an O2 sensor. Good luck. Like.All stuff Jeep related: tech articles, pics, and advice Members Online • Alive_Candidate1755 ... P0420 code upvotes ...Generally, a P0430 means the same thing as a P0420 DTC. The only difference is that the latter shows the problem exists in bank 1. Most four-cylinder and all inline engines have a single bank. So for a proper ... Since there are several causes of a P0430 code on Jeep Grand Cherokee and other car models, there are also several probable solutions ...The most common fix for P0420 in the Jeep Renegade is a new catalytic converter, followed by an O2 sensor replacement. Before taking your Renegade 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 Jeep Renegade: 1. Check for Other Codes.no the code P0420 mean the cat is done not going had it happen to my last car before i bought my jeep i would just do a cat from sumit racing the dynomax one is like 99.00. ... A forum community dedicated to all jeep owners and enthusiasts. Come join the discussion about performance, engine swaps, modifications, classifieds, troubleshooting ...The P0420 code is a generic powertrain code that indicates a problem with the catalytic converter in a vehicle. Specifically for your Jeep Compass, it means that there is a efficiency issue with the catalytic converter in the exhaust system. The code could be triggered by a variety of factors, such as a faulty oxygen sensor or a damaged ...

If you’re an avid DIYer and a car enthusiast, you may have come across the dreaded “Code P0420” at some point. This diagnostic trouble code is related to your vehicle’s catalytic c...The P0420 code means that the converter is not operating at maximum efficiency. There are a few things that can cause this, ... One of the oxygen sensors in your Jeep Grand Cherokee will frequently fail to function properly as a result of the P0420 code being thrown. The code is typically triggered by the upstream oxygen sensor (before the ...bush1355. 11 posts · Joined 2009. #3 · Jan 9, 2021. I have had this code P0420 catalyst efficiency for a few years now. Originally cobe was accompanied by 02 sensor code. (no P code to recall, but P code present) Have had only P0420 since. Dealer said new converter needed ($1300), but running fine in mileage & performance.I bought a '97 SE and it first popped the O2 code, replaced that and then the P0420 came up **a friend ran a carfax for me and there was an open recall on the Jeep - luckily it still had the factory Cat and the dealer replaced it for free under the recall. They used a mopar universal kit that went from the bottom of the exh. manifold to the ...2011 Jeep Compass P0420 Code. A few weeks ago my car started throwing a P0420 (Catalytic converter below threshold). I had the code cleared, it then came back on and proceeded to go back off on its own a week later. It returned a few days ago so now I am trying to figure out if this is a catalytic converter issue or an O2 sensor issue.Recently my jeep has been kicking a P0420 code "Catalyst System Efficency Below Threshold (Bank 1)". ... I still need to fine tune some exhaust adjustments but this took care of my P0420 code for a year. Fast forward to August 2018 and driving around town and bing, P0430 code. This is now bank 2.

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Jeep Liberty P0420 Code Symptoms. The P0420 code in a Jeep Liberty 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.That P0420 codes is one of the most unambiguous of all the diagnostic trouble codes. That code is thrown when the upstream and downstream O2 sensors both have the same "switching frequency." That means that the cat is doing very little to change the exhaust gas composition. In other words, the cat needs to be replaced.The P0420 code indicates that the ECM has detected underperformance of the catalytic converter's efficiency on Bank 1. Either it is a faulty catalytic converter, or it could be an electronic oxygen sensor. The ECM uses two O2 sensors to detect whether the catalytic converter is functioning properly, whether there is a problem with the fuel ...P0420 is a diagnostic trouble code (DTC) for "Catalyst System Efficiency Below Threshold (Bank 1)". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be …

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.2006 Jeep Wrangler with 4.0 liter - throwing codes 133, 431, 339 and 344. Already replaced the cam and crank sensors but no change in engine behavior. Lurches/hiccups occasionaly (sometimes for severa …Even slight variations in the air/fuel mixture will cause the converter temperature to rise significantly. The "Catalytic Converter Efficiency" Diagnostic Trouble Codes (DTCs) P0420 and P0430, are among the top 10 DTCs technicians face. And while the description might imply a failed converter, odds are the ultimate fault lies somewhere else.Jeep Liberty - KJ (02 to 07) ... You can't get P0420/P0430 codes without properly functioning O2 sensors. Nov 21, 2017 #11 A. adamkrz Full Access Member. JoinedCEL - Code P0420, 1.3k miles, 2015 EcoDiesel built in January. So my 2015 Jeep EcoDiesel threw a CEL on my way back from folks this afternoon, about a 45 minute drive. Hot as Hades here in Central Texas today. Threw the code 5 mins after startup. Ran the OBD-II scanner when I got home, saw it was P0420. Just bought the truck in June, it had ...I've replaced both O2 sensors with new ones (NTK) and the code came back. I now need to replace the precat Y pipe. The book calls for the one with the connection (3 bolts) under the passenger seat.Take off the cover and remove the fuse for the controller. Install new fuse with the correct amperage. Reattach the negative battery terminal. Start the ignition to see if the code clears. If the code isn't clear, you'll need to take your car in for further diagnostics.102 posts · Joined 2013. #1 · May 24, 2019. I have been dealing with a frustrating P0420 code. Maybe once a tank (for me that is like a little over a week or so). and then I have to be driving with low RPMs in the 2000-2500 with little if any throttle. It seams to be more likely at half a tank Or less. Engine is most often at full operating ...

This page is meant to help you troubleshoot the Jeep Liberty 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. Jeep Liberty P0430: Symptoms.

Model Specific Jeep Discussions. Wrangler TJ (Model years 1997-2006) TJ Technical Discussion. p0420 code. Jump to Latest Follow 21 - 25 of 25 Posts. 1 2. DoubleOught · Registered. Joined Feb 21, 2014 · 1,209 Posts #21 · Jun 28, 2014. Only show this user. Also agree with you that every 99 4.0 I have seen also had the old style manifolds. ...If the code is happening on a later model Subaru (2015 - present) the chances are it's a bad catalytic converter, otherwise a newer model would throw a specific code for the oxygen sensor if it was the culprit. P0420 Code in Toyota. If you have code P0420 in Toyota models, it's usually due to a faulty catalytic converter.P0133 Jeep Code - O2 Sensor Circuit Slow Response Bank 1 Sensor 1 - Code Popularity: 37,482 Views - Repair Importance Level: 2/3 - Repair Difficulty Level: 2/3. Table of contents. Created and updated by William Orellana on Jun 14, 2020. Possible Causes; Tech Notes; Description; How to Fix;Definition: Catalyst Efficiency (Bank 1) Description: General Operation: The State of Change (SOC) catalyst monitor uses the signals from both the Upstream and Downstream …It also could be that the engine coolant temperature sensor isn't working properly, but I think if that was the issue it would throw a separate code. Code P0420 is catalyst efficiency bank 1 (passenger side). You can check on-line how to test an O2 sensor. Good luck. Like.FOLLOW THIS GUIDE if you have a P0420 code. I will explain what the code means, how to diagnose it, and all that backed up by 100+ fixes case study, where I. ... 2012 Jeep Compass Limited 2.4L: MIL disappeared by itself: 2016 Honda Accord EX-L 2.4L: O2 sensor short circuit: 2002 Subaru Legacy L 2.5L: O2 sensors: 1999 Honda CR-V EX 2.0L:P0420 Code 2007 3.8L JK. A couple of months ago the P0420 was thrown. I reset it with the BlueDevil OBD II tool. But after a series of trips it reappears. The catalytic converter had been replaced in 2017 and the vehicle only has about 5000 more miles on it since then. I replaced all four Oxygen sensors again to be sure but still the same problem.Exhaust leak. 1. Faulty Catalytic Converter. A P0420 code will most likely appear if your catalytic converter is malfunctioning. This is the case because the converter is in charge of converting toxic emissions into less harmful gases. As a result, if it's damaged, it might create a slew of problems with your vehicle.Sirius satellite radio is available in many new cars, including Jaguar, Mazda, Ford, Jeep, Chrysler, Dodge, Mercedes-Benz, BMW, Volvo, Volkswagen and Audi vehicles. If your new car...A code P0420 may mean that one or more of the following has happened: •Leaded fuel was used where unleaded was called for. •An oxygen sensor is not reading (functioning) properly. •The engine coolant temperature sensor. is not working properly. •Damaged or leaking exhaust manifold / catalytic converter / exhaust pipe.

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December 18, 2019 by Jason. P0520 is a common OBD2 trouble code. It’s generic, which means that it has the same meaning for the Jeep Renegade as it would any other vehicle. P0520 indicates that the oil pressure sensor is operating outside of its normal “range”. It is typically caused by a bad oil pressure sensor switch or a wiring problem.How to diagnose code P0420 on a Jeep Compass. 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 flow ...DTC code P0420 ? Catalyst System Efficiency Below Threshold (Bank 1)Catalyst 1/1 efficiency below required level. ok so i cleared out the code twice and after a few days both times it pops back up. should i change the o2 sensors or just take it to the dealer and try to have them replace the cat under warranty? i have 29000 miles.P0420 Code. Hi, new to the forum and new Jeep owner. I've got a 2007 Grand Cherokee Limited with the 5.7. I had it checked out before I bought it and it showed a fault with a downstream O2 sensor which I replaced, the CEL was cleared, and I drove it 50 miles on the highway. Light stayed off for about a day.Popular Engine Codes p0420 code p0172 code p00171 code p0128 code p0300 code p0456 code p0430 code p0442 code p0455 code p0113 code. ... Toyota 4Runner vs. Jeep Grand Cherokee | The Best Model Year For Every Budget 72 Car Safety Tips For Drivers Of All Ages & Stages DOWNLOAD THE APP. About. About FIXD; Editorial Process;I found fault code p0420 with my reader..catalytic..O2 sensors - Answered by a verified Jeep Mechanic. We use cookies to give you the best possible experience on our website. ... 2008 Jeep Wrangler codes p0430 and p0420. Need help diagnosing.Trouble code P0420 means:Catalyst system efficiency below threshold Has Jeep Cherokee Limited 2003 has same gearbox as Jeep Grand Cherokee? There wasn't a 2003 Cherokee.JEEP CHEROKEE CODE P0420 CATALYTIC CONVER CODE FIX, ENGINE LIGHT ONIf you have Jeep Cherokee and you have Code P0420 and your engine light is on we will expl... ….

I have a 2007 that I bought last year and yesterday while driving back from Stone Mountain the Check Engine Light came on. When I checked the code it was P0430. The local AutoZone suggested replacing the passenger O2 just past the cat. I replaced it but have not reset the system yet.P0420 code..02 Sensors or Cat replacement? Jump to Latest Follow 21 - 27 of 27 Posts. 1 2. M. Mp5ben · Registered. Joined Feb 28, 2011 · 1,500 Posts ... Any other problems with the Jeep? For both to go at nearly the same time makes me wonder if there's something else going on. Of course, the catalytic converters are twins born at the same ...When left unattended, a P0456 Jeep code can lead to compounded performance issues and huge repair expenses. That said, it is best to pick up on its symptoms early on. P0456 Jeep code symptoms include: A triggered Check Engine Light. Starting difficulties. Fuel odors in your cabin.=====Claim your FREE engine code eraser 👉 https://free.nonda.co 👈=====Engine Code JEEP P0038 Saving Repair ...1 post · Joined 2019. #1 · Jan 18, 2019. 2010 Jeep Wrangler Unlimited Rubicon 3.8L. 280,032 miles. Code P0401 Problem. I installed my 2nd EGR Valve but I still get the code. I even Just replaced last night all 4 O2 sensors That I got from Jeep dealer parts department. Drove it 150 miles the only thing that comes up now is P0401 again.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. P0421 – “Warm Up Catalyst Efficiency Below Threshold (Bank 1)”. P0422 – “Main Catalyst Efficiency Below Threshold (Bank 1)”. P0423 – “Heated ...A suspect is wrong sensors. 3) check fuse #16 in PDC and relay oxygen downstream in PDC. a wag - INCORRECT O2 SENSORS, let us know. P0138-1/2 O2 SENSOR SHORTED TO VOLTAGE. P0420-1/1 CATALYTIC CONVERTER EFFICIENCY. P0141-1/2 O2 SENSOR HEATER FAILURE. P0161-2/2 O2 SENSOR HEATER FAILURE.Here's how to modify your car's oxygen sensor to get rid of a P0420 OBDII code, clear the check engine light and pass an emissions test.The P0420 code is thr...P0420 Code Jeep Grand Cherokee. P0456 code jeep liberty 2000 jeep grand cherokee 4.7. codes. p1596, p0204, p0207. how to repair? Jeep ba16. 9-24-13 2008 Jeep Grand Cherokee 3.7 code P0325 Part 2 - YouTube. Jeep p0420 code, Trouble code P0420 means:Catalyst system efficiency below threshold Has Jeep Cherokee Limited 2003 has same gearbox as Jeep Grand Cherokee? There wasn't a 2003 Cherokee., Recently my jeep has been kicking a P0420 code "Catalyst System Efficency Below Threshold (Bank 1)". ... I still need to fine tune some exhaust adjustments but this took care of my P0420 code for a year. Fast forward to August 2018 and driving around town and bing, P0430 code. This is now bank 2., 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..., Unfortunately, the P0420 is a fairly straight forward code, and a fairly common problem. This code points to a failing Catalytic Converter. The Oxygen Sensors measure the amount of emissions in the exhaust going into, and then out of the converter. When they see that the converter is not "cleaning" the exhaust enough to meet specs, …, With a P0128 code, the first step is to get it properly diagnosed to figure out what is causing the malfunction in the coolant temperature circuit. Using the live data function of the FIXD sensor and app allows you to read and analyze engine temperatures to properly diagnose a P0128 code. >Click here to get FIXD for just $19.99 for a limited time!, Code P0420 Jeep Description The Engine Control Module ( ECM ) monitors the switching frequency ratio of heated oxygen sensors 1 (front O2 sensor) and heated oxygen sensors 2 (rear O2 sensor). A three way catalyst converter (Manifold) with high …, =====Claim your FREE engine code eraser 👉 https://free.nonda.co 👈=====Engine Code JEEP P0038 Saving Repair ..., =====Claim your FREE engine code eraser 👉 https://free.nonda.co 👈=====Engine Code JEEP P0038 Saving Repair ..., Tech Notes. As the code description implies the P0420 code means that the vehicle's control module has detected that the three-way catalytic converter is not working properly (it is not as efficient as the factory is expecting). Replacing the oxygen (O2) sensors may sometimes fix the code, but in most cases, the catalytic convert needs to be ..., P0420 Code 2007 3.8L JK. A couple of months ago the P0420 was thrown. I reset it with the BlueDevil OBD II tool. But after a series of trips it reappears. The catalytic converter had been replaced in 2017 and the vehicle only has about 5000 more miles on it since then. I replaced all four Oxygen sensors again to be sure but still the same problem., How to diagnose code P0420 on a Jeep Patriot. 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 flow ..., The most common fix for P0420 in the Jeep Renegade is a new catalytic converter, followed by an O2 sensor replacement. Before taking your Renegade 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 Jeep Renegade: 1. Check for Other Codes., I have a 2007 that I bought last year and yesterday while driving back from Stone Mountain the Check Engine Light came on. When I checked the code it was P0430. The local AutoZone suggested replacing the passenger O2 just past the cat. I replaced it but have not reset the system yet., P0420 jeep tj 2000 wrangler 2017 jeep wrangler p0306Wrangler jeep p0304 code misfire trouble relatively obd2 includes common vehicle any 46e0 7ad4 8cf5P0420 jeep. Diagnose and fix jeep wrangler p0457Jeep wrangler tj p0456 p0455 trouble evac repair codes Wrangler p0456 evap obdiiGot code p0325 on 2009 jeep wrangler x, where is the knock sensor ..., 2009 3.7 V6 WK 133,000 miles. Unlikely that cleaning throttle body killed the Cat. Manually moving the throttle should produce no issues. Have someone put a scanner or oscilloscope on the front and rear O2 sensors to confirm the P0420. That person will look at the wave forms of each O2 sensor., Ok yall here is my question. I have 2x now gotten a P0420 code and 1x a P0432 code. My OBD readings for both Bank 1 sensors are fluctuating between .08 v and .800v. Both Bank 2 sensors are also fluctuating like both Bank 1. Any ideas if its just my 02's post cat are bad or if its something..., P0420 Code. Hi, new to the forum and new Jeep owner. I've got a 2007 Grand Cherokee Limited with the 5.7. I had it checked out before I bought it and it showed a fault with a downstream O2 sensor which I replaced, the CEL was cleared, and I drove it 50 miles on the highway. Light stayed off for about a day., O2 sensor part numbers? Filled my '12JKUR (80,000 miles) with ARCO gas, which is supposed to be Top Tier, and a few miles down the road, check engine light comes on; codes were P0430 (cat insufficiency) and P0158 sensor 2/2 (driver's side?). Took it into dealer and they said replace all 4 cat converters and all 4 sensors for $3600!, 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 …, Overall probably the biggest mistake vehicles owners make when they have a P0420 code is to simply replace an oxygen sensor (H02S). It is important to do proper diagnosis so you're not wasting money replacing parts unnecessarily ... Find answers to all your Jeep Patriot technical questions. Show Less . Full Forum Listing. Explore Our Forums., 2 posts · Joined 2021. #1 · Nov 28, 2021. Newbie here. Not mechanically knowledgeable. Just bought my 2014 Patriot used. Passed inspection but now check engine light came on (steady) and took to dealer who pulled this code PO420. Dealer wants 1570 for new maniverter catalytic converter. Reset light, but it came on again., 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 converter in an engine with two cylinder banks (e.g., V6 or V8). The catalytic converter or "cat" is a key component of the vehicle emission control ..., Tech Notes. The P0440 code means that the control module has detected a leak in the Evaporative Emission (EVAP). Loose fuel tank filler cap is the most common cause that triggers the P0440 code. ⚠ Check if your Jeep have Safety Recalls., This page is meant to help you troubleshoot the Jeep Commander 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. Jeep Commander P0430: Symptoms., 6.Get a Replacement O2 Sensor That Fits Your Car. The P0157 code refers to a potential problem with the #2 sensor on Bank 2 or its circuit. This code applies to the downstream oxygen sensor located right behind the catalytic converter. If your OBD-II scanner registers this code, you can either let your mechanic handle it or address the issue ..., The P0420 is a diagnostic trouble code mainly for Catalytic System Efficiency Below Threshold (Bank1). This code is stored in memory when the ECM would have detected a low efficiency in the catalytic system. The ECM determines the cat con's working efficiency with two sensors. As such, the Catalytic System Efficiency (CSE) metric regulates ..., This page is meant to help you troubleshoot the Jeep Wrangler 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. Jeep Wrangler P0430: Symptoms., Durango p0456 evap leak symptoms obdii Dodge durango 3.6l p0128 code How to fix obd code p0420 on a dodge durango Check engine light on my 2016 dodge challenger hellcat ... my durango just dies when im at a light or stoppedCode p0420 dodge dart, chrysler 200, jeep cherokee compass renegade Catalytic p0430 p0420 catalyst threshold theft protect ..., To diagnose the P0420 2018 Chevrolet Silverado code, it typically requires 1.0 hour of labor. The specific diagnosis time and labor rates at auto repair shops can differ based on factors such as the location, make and model of the vehicle, and even the engine type. It is common for most auto repair shops to charge between $75 and $150 per hour., 96XJ 4.0L Check Engine Code PO420. Check engine light came on, had it scanned at the dealership and the local auto hobby shop and came up with the same code, (PO420). The catylitic converter on there was a "Random Technology, Level-1" I had purchased from Quadratec and had installed some years back along with new (2) OEM O2 sensors at the time ..., 2005 Jeep Liberty check engine light and P0420 code. 2005 Jeep Liberty check engine light and P0420 code. Analyzed by shop as catalytic converter being bad. Caused by engine burning oil; blue smoke from exhaust., Remove rear o2 sensor. Install the anti-fouler then screw o2 sensor back in. This will solve your p420 cell but its just a bandaid if your cat is really bad. P0420 is bank 1 sensor 2. So if you got two pre-cats then do this mod to the after pre-cat sensor on the front set of pipes. D., Summary. DTC P0520 stands for "Engine Oil Pressure Sensor/Switch "A" Circuit.". This is logged when the PCM detects problems with the oil pressure sensor, oil pressure switch, or the oil pressure in general. Code P0520 is usually triggered because of faulty oil pressure sensors, bad circuitry, and low oil pressure.