Descripción del código DTC P0171 CHEVY Chevy. El código P0171 en un modelo chevy indica que el O2 (Oxygen Sensor) situado en el banco 1, ha detectado que existe una condición pobre, es decir que el Sensor de oxigeno (O2) encuentra un exceso de oxígeno en la mezcla aire/combustible. El banco 1 se refiere al lado del motor que tiene el ...In this video, I show you how I troubleshoot a Check Engine Light (CEL) / Diagnostic Trouble Code (DTC) P0171, System Too Lean Bank 1. The exact vehicle in ...Some possible causes of a P0171 engine code are. Vacuum leak. Weak fuel pump. Broken fuel pressure regulator. Blocked fuel filter. Faulty powertrain control module. Defective injectors. Faulty oxygen sensors. Clogged catalytic converter. The most common causes for this code are a vacuum leak, a bad oxygen sensor, and a failed mass air flow sensor. Code p0171 in a chevy sonic means that the fuel system is running too lean. First scaned 7 codes for oxy sensor,, erased all and scaned again all seven came backCheck ecm-3 fuse. Number 24 fuse Replace the blown, all codes for oxy ...The P0496 code indicates that there’s an incorrect amount of intake vacuum flow occurring in the car’s EVAP system. Any time this vacuum is higher than what the computer determines is appropriate, the codes will be set. While this code can occur with all brands, it appears to be most common with GM vehicles.Chevrolet Cruze 2016 2019 1.4L (RPO LE2) Equinox 2018 2020 1.5L (RPO LYX) Malibu 2016 2020 1.5L (RPO LFV) Trax 2019 2019 1.4L (RPO LE2) Volt 2016 2019 1.5L (RPO L3A) GMC Terrain 2018 2020 1.5L (RPO LYX) Involved Region or Country North America, China, Thailand, GM Korea, Middle East, Israel, Europe, Brazil, Chile, Colombia, Peru, South Africa ...My initial thought was that P0017 was causing P0171. When I reset the codes, 0017 would come back within a minute of running the engine. 0171 would show up after driving the vehicle for 30-40 miles. I first focused on 0017. I've changed the actuator solenoid ( 3 times), camshaft position sensor, crankshaft sensor.Jul 25, 2020 · A P1174 & P1175 trouble code means that your air to fuel ratio is either running too lean or too rich. Engines will have two banks. In traditional V-shaped engines, the 2-4 cylinders (depending on whether it is a V4 or V8, etc.) on the left side are considered “Bank 1” and the cylinder on the left are considered “Bank 2”. May 16, 2020 · The video focuses on the basic GMC specific diagnostic error code.Contents:0:21 Basic DTC analysis according to OBD2 protocol standard.1:48 Insight into prog... P0171 indicates that your Chevy Cruze is either getting too much air or not enough fuel. A clogged or damaged fuel injector will cause the air-fuel mixture to lean out in one specific cylinder. You may see a cylinder misfire code or fuel injector-specific code with P0171. If you have one or more fuel injectors that have gone bad, that can cause ...P0171 is an OBDII trouble code. The code technically stands for: The code is thrown when the oxygen sensors detect that there’s not enough oxygen in the exhaust system. This is commonly referred to as a “lean” condition. The vehicles ECM will add more fuel to the mixture in order to bring the air fuel mixture where it needs to be for ...The cost of P11011 issues on a Chevy Cruse depends on the cause. OEM air filters cost less than $30 for all engine types, so this is a budget-friendly place to start diagnosing the problem. An OEM ...P0010 definition: Intake Camshaft Actuator Circuit Open/Short (Bank 1) Issue Severity: MODERATE – Extended driving with this code may cause internal engine damage. Repair Urgency: Get this code fixed as soon as possible to avoid loss of power, fuel economy, and damage to your emission system. Diagnosis: This trouble code will not prevent your ...Fuel Injectors. P0171 indicates that your GMC Envoy is either getting too much air or not enough fuel. A clogged or damaged fuel injector will cause the air-fuel mixture to lean out in one specific cylinder. You may see a cylinder misfire code or fuel injector-specific code with P0171. If you have one or more fuel injectors that have gone bad ...Apr 22, 2023 · The P0420 trouble code is more common in some car models than others. Certain car models are known to have a problem with this diagnostic trouble code. Here is a list of the most common causes by car brands. Remember that these are only general guidelines, and you should make a diagnosis before replacing any parts. 1. Chevrolet This diagnostic trouble code (DTC) is a generic powertrain code. It is considered generic because it applies to all makes and models of vehicles (1996-newer), although specific repair steps may be slightly different depending on the model. The DTC P0452 is relates to an emission system malfunction. Your PCM or powertrain management computer ... Indicator Lamp (MIL) Illuminated - DTCs P0300-P0308, P050D, P0171, P0172, P0174, P0175, P2099, P219A, and/or P219B Set Attention: This bulletin applies to V6 and V8 Gasoline Engines ONLY. The vehicle being worked on is a 2004 Chevy Suburban with a 5.3L engine. It had multiple trouble codes in memory P0171 and P0174 (fuel system too lean bank 1...May 21, 2023 · The P0700 code indicates that the transmission control module (TCM) detected a problem with the transmission parameters. It communicates with the engine control module (ECM) to set the Malfunction Indicator Lamp (MIL) when the fault is detected. P0700 is not a specific code. The Engine Control Module (ECM) uses the MAF sensor signal to provide the correct fuel delivery for all engine speeds and loads. The Diagnostic Trouble Code (DTC) will be set if the ECM detects that the measured MAF is not within a calibrated range of the model for greater than 2 seconds. P1101 Chevrolet Code - Intake Air Flow System Performance.Indicator Lamp (MIL) Illuminated - DTCs P0300-P0308, P050D, P0171, P0172, P0174, P0175, P2099, P219A, and/or P219B Set Attention: This bulletin applies to V6 and V8 Gasoline Engines ONLY.Jul 11, 2018 · The mass air flow sensor calculates the volume of air entering the engine. If it has gone bad, the air fuel mixture will be off and the P0174 and/or P0171 codes will show. It’ll be located between the air filter and the throttle body. It’s easy to find. It will have a wiring harness plugged into it. Jun 12, 2023 · The MAP sensor signal should be 1 to 4.5 volts, heading back to the PCM, depending on what load the engine is running at. If the P0106 code is set, it means that the signal went below or above that for a predetermined amount of time. This code is defined as generic by the SAE (Society of Automotive Engineers). Chevrolet Codes; Trouble Code Fault Location Probable Cause; B1325: Control Module Power Circuit Low/High Voltage: P0014: Camshaft position (CMP) exhaust/right/rear, bank 1 -timing over -advanced/system performance: P0171: System too lean, bank 1: Intake/exhaust leak, AIR system, MAFNAF sensor, fuel pressure/pump, injector(s), HO2S: P0174 ... P0496 definition: EVAP Flow During a Non-Purge Condition. Issue Severity: LOW – Continued driving for a short period of time is okay. Repair Urgency: Get this fixed within the next month to prevent catalytic converter damage. Diagnosis: There may not be any noticeable driving issues with your vehicle, but your engine could be running rich ...Feb 21, 2022 · P0171 definition: Bank 1 has too much air or not enough fuel. Issue Severity: MODERATE– Extended driving with this code can cause internal engine damage. Repair Urgency: Get this code fixed as soon as possible to avoid damage to spark plugs, pistons, and catalytic converters. Diagnosis: It is important to complete the entire diagnostic ... Diagnosis: Driving with trouble code P0137 is acceptable but only for a short period of time. Driving with this code for an elongated period of time could result in greater engine damage if it is being caused by a lean air/fuel ratio. Common Reason: Code P0137 is often related to a bad O2 Sensor. Oxygen sensor 2 is the downstream oxygen sensor ...P0010 definition: Intake Camshaft Actuator Circuit Open/Short (Bank 1) Issue Severity: MODERATE – Extended driving with this code may cause internal engine damage. Repair Urgency: Get this code fixed as soon as possible to avoid loss of power, fuel economy, and damage to your emission system. Diagnosis: This trouble code will not prevent your ...Automobile Repair Shop Owner. Code. Fault Location. Probable Cause. P0171. Fuel System Too Lean Bank 1. (Buy Part On Amazon) Intake/exhaust leak, AIR system, MAFNAF sensor, fuel pressure/pump, injector (s), HO2S. We recommend Torque Pro.OBD II fault code P0455 is a generic code that is defined as “Evaporative Emission System Leak Detected (large leak), and is most commonly set when the PCM (Powertrain Control Module) detects a large leak in the evaporative emissions control system. NOTE: Note that on many applications, this code has a dual definition, in the sense that it ...This particular Cruze is a 2012 1.4 Turbo but this procedure is very similar to allot of Chevy ans other years Cruze's.Recently I had been felling the car ru...May 25, 2022 · Tools needed for diagnosing advanced P0171 code causes: OBD II scanner or code reader. Carburetor or throttle body cleaner. 1. Disconnected or Leaking Hoses. Air Intake Hose: Find the air intake hose that connects to the engine. Grab and shake it so you can feel if anything is loose. Oct 25, 2019 · Brian Eslick from How to Automotive http://www.howtoautomotive.com takes you step-by-step through the process of diagnosing code P0171-P0174 lean bank 1 and ... Jul 23, 2018 · One of the most common trouble codes with the Chevy Malibu is P0171. It indicates that your Chevy Malibu is running lean on the bank one side. It’s the most common air/fuel mixture-related code. It’s not the most complicated OBDII trouble code to diagnose. It is also one of the most common codes. P0171 is a known issue in Malibu’s with ... One of the most common trouble codes with the Chevy Malibu is P0171. It indicates that your Chevy Malibu is running lean on the bank one side. It’s the most common air/fuel mixture-related code. It’s not the most complicated OBDII trouble code to diagnose. It is also one of the most common codes. P0171 is a known issue in Malibu’s with ...One of the most common trouble codes with the Chevy Malibu is P0171. It indicates that your Chevy Malibu is running lean on the bank one side. It’s the most common air/fuel mixture-related code. It’s not the most complicated OBDII trouble code to diagnose. It is also one of the most common codes. P0171 is a known issue in Malibu’s with ...P0171 and P0174 occur when the air/fuel mixture on the vehicle gets too lean. They are both thrown when the oxygen sensors detect that there is not enough oxygen in the exhaust. The engine then makes adjustments to compensate and throws these codes, which trigger the service engine soon light. When these codes both appear at the same time, it ...Automobile Repair Shop Owner. Code. Fault Location. Probable Cause. P0171. Fuel System Too Lean Bank 1. (Buy Part On Amazon) Intake/exhaust leak, AIR system, MAFNAF sensor, fuel pressure/pump, injector (s), HO2S. We recommend Torque Pro.Feb 6, 2019 · In this video I have a look at a 2008 Chevrolet Silverado 1500 5.3 that came in with codes P0171 and P0174 indicating that the engine is running lean. It doe... P0171 indicates that your Chevy Corvette is either getting too much air or not enough fuel. A clogged or damaged fuel injector will cause the air-fuel mixture to lean out in one specific cylinder. You may see a cylinder misfire code or fuel injector-specific code with P0171. If you have one or more fuel injectors that have gone bad, that can ...What is the Cost to Diagnose the Code P015B Chevrolet? Labor: 1.0. The cost to diagnose the P015B Chevrolet code is 1.0 hour of labor. The diagnosis time and labor rates at auto repair shops vary depending on the location, make and model of the vehicle, and even the engine type. Most auto repair shops charge between $75 and $150 per hour. P0171 indicates that your Chevy Cruze is either getting too much air or not enough fuel. A clogged or damaged fuel injector will cause the air-fuel mixture to lean out in one specific cylinder. You may see a cylinder misfire code or fuel injector-specific code with P0171. If you have one or more fuel injectors that have gone bad, that can cause ...The MAP sensor signal should be 1 to 4.5 volts, heading back to the PCM, depending on what load the engine is running at. If the P0106 code is set, it means that the signal went below or above that for a predetermined amount of time. This code is defined as generic by the SAE (Society of Automotive Engineers).Potential causes of a P0496 EVAP code include: Faulty purge or vent solenod/valve. Plugged EVAP canister. Failed EVAP / fuel pressure sensor. Poor electrical connection. Short electrical circuit condition. (Hyundai, Isuzu) Faulty canister purge valve. Blocked vapor canister.While some trouble codes leave vehicle owners with a plethora of possible causes, the P0449 code likely only has one of three possible causes. First, the vent valve in the evaporative emissions system might be faulty. Second, the connection, wires, or circuits in the system might be having a connectivity issue that is causing a false reading. P0171 indicates that your Chevy Trax is either getting too much air or not enough fuel. A clogged or damaged fuel injector will cause the air-fuel mixture to lean out in one specific cylinder. You may see a cylinder misfire code or fuel injector-specific code with P0171. If you have one or more fuel injectors that have gone bad, that can cause ...Subject: Information on Malfunction Indicator Lamp (MIL) Illuminated - DTC P0171 Set This Bulletin replaces PIP5197M. Please discard PIP5197M. Brand: Model: Model Year: VIN: Engine: Transmission: from to from to Buick Encore 2013 2019 1.4L (LUJ, LUU, LUV) Cadillac ELR 2014 2017 Chevrolet Cruze 2011 2016 Sonic 2012 2019 Trax 2013 2019 Volt 2012 2015Descripción del código DTC P0171 CHEVY Chevy. El código P0171 en un modelo chevy indica que el O2 (Oxygen Sensor) situado en el banco 1, ha detectado que existe una condición pobre, es decir que el Sensor de oxigeno (O2) encuentra un exceso de oxígeno en la mezcla aire/combustible. El banco 1 se refiere al lado del motor que tiene el ...Mar 29, 2015 · My initial thought was that P0017 was causing P0171. When I reset the codes, 0017 would come back within a minute of running the engine. 0171 would show up after driving the vehicle for 30-40 miles. I first focused on 0017. I've changed the actuator solenoid ( 3 times), camshaft position sensor, crankshaft sensor. How to Fix the U0107 Code. Before attempting to do any repairs, know that the repair processes for OBD-II trouble codes can vary greatly. There’s no single way to cure the problems causing any DTC because different vehicle models are designed differently.SOURCE: Ford windstar OBD II code P1537/38, P0171 and P0420. It could all be related.P1537/38 are the intake manifold runner controls are stuck open.They are controlled by vacuum solenoids.The P0171 is bank one of the engine is running lean,usually caused by a vacuum leak, P0420 is catalytic converter efficiency code.The P0171 code indicates that the fuel system in part of the engine is running weak or there is a vacuum leak near that side of the engine. This happens when the engine is getting too little gas or too much air. Now let’s go over a bit of Chevy Cruze history. Then we will go into more detail about the P0171 code.Jul 25, 2020 · A P1174 & P1175 trouble code means that your air to fuel ratio is either running too lean or too rich. Engines will have two banks. In traditional V-shaped engines, the 2-4 cylinders (depending on whether it is a V4 or V8, etc.) on the left side are considered “Bank 1” and the cylinder on the left are considered “Bank 2”. May 16, 2020 · The video focuses on the basic GMC specific diagnostic error code.Contents:0:21 Basic DTC analysis according to OBD2 protocol standard.1:48 Insight into prog... Problem is, you aren’t sure how to fix Silverado P0171 problems in your Chevy truck. Not to worry, because today I’ll be showing you how to clear your Silverado check engine light and fix your P0171 trouble code. The P0171 GM OBDII DTC Trouble Code relates to the Powertrain Control Module (PCM) seeing too much air from the upstream oxygen ...The most common cause of the P0171 code – and the P0170 and P0173-P0174 codes – is unmetered air entering the combustion system. Most of the time, this happens due to faulty or dirty mass ... P0171 indicates that your Chevy Cruze is either getting too much air or not enough fuel. A clogged or damaged fuel injector will cause the air-fuel mixture to lean out in one specific cylinder. You may see a cylinder misfire code or fuel injector-specific code with P0171. If you have one or more fuel injectors that have gone bad, that can cause ...Jun 12, 2023 · The MAP sensor signal should be 1 to 4.5 volts, heading back to the PCM, depending on what load the engine is running at. If the P0106 code is set, it means that the signal went below or above that for a predetermined amount of time. This code is defined as generic by the SAE (Society of Automotive Engineers). One of the most common trouble codes with the Chevy Malibu is P0171. It indicates that your Chevy Malibu is running lean on the bank one side. It’s the most common air/fuel mixture-related code. It’s not the most complicated OBDII trouble code to diagnose. It is also one of the most common codes. P0171 is a known issue in Malibu’s with ...Code P0171 GMC Tech Notes. The P0171 code means that more air than gasoline is detected in the exhaust gases exiting the combustion chamber. If the P0171 is set in along with the P0174 code, it is highly likely that the problem is caused by an intake leak. If there are no intake leaks, the next step is to replace the air filter and clean the ...Potential causes of a P0496 EVAP code include: Faulty purge or vent solenod/valve. Plugged EVAP canister. Failed EVAP / fuel pressure sensor. Poor electrical connection. Short electrical circuit condition. (Hyundai, Isuzu) Faulty canister purge valve. Blocked vapor canister.The following are the most common causes of the P0174 code. Faulty mass airflow (MAF) sensor. Blockage in the fuel filter and fuel injectors. The fuel pump is getting weak. Weakening fuel pressure regulator. The vacuum connector or PCV line may have cracks or damage. Defective oxygen sensor. Issues with PCM. What the P1101 code means. When a P1101 trouble code is stored, it means that the PCM detected a discrepancy with the voltage from the MAF sensor. This problem can be detected while the PCM is running a self diagnostic called a Key On Engine Running (KOER) test. When the voltage from the MAF sensor is greater or lesser than the voltage allowed ...Jul 18, 2018 · P0171 indicates that your Chevy Impala is either getting too much air or not enough fuel. A clogged or damaged fuel injector will cause the air-fuel mixture to lean out in one specific cylinder. You may see a cylinder misfire code or fuel injector-specific code with P0171. If you have one or more fuel injectors that have gone bad, that can ... To diagnose the P0171 Chevrolet 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.Jun 12, 2023 · The MAP sensor signal should be 1 to 4.5 volts, heading back to the PCM, depending on what load the engine is running at. If the P0106 code is set, it means that the signal went below or above that for a predetermined amount of time. This code is defined as generic by the SAE (Society of Automotive Engineers). Sep 12, 2017 · This particular Cruze is a 2012 1.4 Turbo but this procedure is very similar to allot of Chevy ans other years Cruze's.Recently I had been felling the car ru... Brian Eslick from How to Automotive http://www.howtoautomotive.com takes you step-by-step through the process of diagnosing code P0171-P0174 lean bank 1 and ...Nov 26, 2019 · Problem is, you aren’t sure how to fix Silverado P0171 problems in your Chevy truck. Not to worry, because today I’ll be showing you how to clear your Silverado check engine light and fix your P0171 trouble code. The P0171 GM OBDII DTC Trouble Code relates to the Powertrain Control Module (PCM) seeing too much air from the upstream oxygen ... The P0420 trouble code is more common in some car models than others. Certain car models are known to have a problem with this diagnostic trouble code. Here is a list of the most common causes by car brands. Remember that these are only general guidelines, and you should make a diagnosis before replacing any parts. 1. ChevroletJul 31, 2018 · P0171 indicates that your Chevy Corvette is either getting too much air or not enough fuel. A clogged or damaged fuel injector will cause the air-fuel mixture to lean out in one specific cylinder. You may see a cylinder misfire code or fuel injector-specific code with P0171. If you have one or more fuel injectors that have gone bad, that can ... The most common causes of P0171 are a bad Oxygen sensor, a vacuum leak, or a dirty MAF sensor. P0171: Fuel Trim System Lean (Bank 1). Check engine light, decreased fuel economy, misfire, hard to find idle. Dirty MAF sensor, vacuum leak, O2 sensor.P0171 definition: Bank 1 has too much air or not enough fuel Issue Severity: MODERATE– Extended driving with this code can cause internal engine damage. Repair Urgency: Get this code fixed as soon as possible to avoid damage to spark plugs, pistons, and catalytic converters.Oxygen Sensor. The P0171 code is thrown when the bank one sensor one O2 sensor reports that your Cobalt’s engine is running lean. The sensor on or right after the exhaust manifold is typically the sensor that reports the lean condition. If it is malfunctioning, it can cause a false P0171 code.Jul 14, 2018 · P0171 indicates that your Chevy Cruze is either getting too much air or not enough fuel. A clogged or damaged fuel injector will cause the air-fuel mixture to lean out in one specific cylinder. You may see a cylinder misfire code or fuel injector-specific code with P0171. If you have one or more fuel injectors that have gone bad, that can cause ... Jul 25, 2020 · A P1174 & P1175 trouble code means that your air to fuel ratio is either running too lean or too rich. Engines will have two banks. In traditional V-shaped engines, the 2-4 cylinders (depending on whether it is a V4 or V8, etc.) on the left side are considered “Bank 1” and the cylinder on the left are considered “Bank 2”. The video focuses on the basic GMC specific diagnostic error code.Contents:0:21 Basic DTC analysis according to OBD2 protocol standard.1:48 Insight into prog...Jun 7, 2018 · P0171, P0174 GM vehicles P0171, P0174 GM vehicles Diagnose and fix P0171, P0174 GM vehicles Service bulletin #PIP5549 for P0171, P0174 GM vehicles. GM has issued service bulletin #PIP5549 to address trouble codes P0171, P0174 on GM vehicles listed below. Vehicles affected. Buick Enclave 2012-2018 3.6 LLT, 3.6LFY engines. Cadillac XTS 2015-2018 ...
The P0171 OBD-II code means that, on the first bank of the engine, the fuel system is running weak or a vacuum leak exists near this side of the engine. A lean condition occurs when the engine either receives too little fuel or too much air. What are the causes of the P0171 code? Causes of the P0171 code may include: A faulty fuel pressure .... Leon gary plauche reddit
Oct 24, 2008 · SOURCE: Ford windstar OBD II code P1537/38, P0171 and P0420. It could all be related.P1537/38 are the intake manifold runner controls are stuck open.They are controlled by vacuum solenoids.The P0171 is bank one of the engine is running lean,usually caused by a vacuum leak, P0420 is catalytic converter efficiency code. The P0171 code is thrown when the bank one sensor one O2 sensor reports that your Equinox’s engine is running lean. The sensor on or right after the exhaust manifold is typically the sensor that reports the lean condition. If it is malfunctioning, it can cause a false P0171 code.In this video, I show you how I troubleshoot a Check Engine Light (CEL) / Diagnostic Trouble Code (DTC) P0171, System Too Lean Bank 1. The exact vehicle in ...Jul 18, 2018 · P0171 indicates that your Chevy Impala is either getting too much air or not enough fuel. A clogged or damaged fuel injector will cause the air-fuel mixture to lean out in one specific cylinder. You may see a cylinder misfire code or fuel injector-specific code with P0171. If you have one or more fuel injectors that have gone bad, that can ... Code P0171 GMC Tech Notes. The P0171 code means that more air than gasoline is detected in the exhaust gases exiting the combustion chamber. If the P0171 is set in along with the P0174 code, it is highly likely that the problem is caused by an intake leak. If there are no intake leaks, the next step is to replace the air filter and clean the ...Sep 16, 2019 · Your car or truck has either a P0171, P0174 lean fault code or both stored in the pc, these codes derive from Oxygen Sensor (O-2) readings. A lean code or codes suggest that there surely is too-much air in the exhaust. Bear in mind parts shops have staff members having good motives nonetheless they may not have the experience necessary to ... Jan 27, 2021 · Automobile Repair Shop Owner. Code. Fault Location. Probable Cause. P0171. Fuel System Too Lean Bank 1. (Buy Part On Amazon) Intake/exhaust leak, AIR system, MAFNAF sensor, fuel pressure/pump, injector (s), HO2S. We recommend Torque Pro. P0171 indicates that your Chevy Impala is either getting too much air or not enough fuel. A clogged or damaged fuel injector will cause the air-fuel mixture to lean out in one specific cylinder. You may see a cylinder misfire code or fuel injector-specific code with P0171. If you have one or more fuel injectors that have gone bad, that can ...Mar 17, 2023 · Code Definition P0171 – System Too Lean (Bank 1) What does the P0171 code mean? The P0171 code indicates that the oxygen (O2) sensor on bank 1 sent a signal to the engine control module that the air-fuel mixture is too lean to be corrected. The O2 sensors have the ability to correct a fuel mixture of +-15%. The P0700 code indicates that the transmission control module (TCM) detected a problem with the transmission parameters. It communicates with the engine control module (ECM) to set the Malfunction Indicator Lamp (MIL) when the fault is detected. P0700 is not a specific code.Some possible causes of a P0171 engine code are. Vacuum leak. Weak fuel pump. Broken fuel pressure regulator. Blocked fuel filter. Faulty powertrain control module. Defective injectors. Faulty oxygen sensors. Clogged catalytic converter. The P0420 trouble code is more common in some car models than others. Certain car models are known to have a problem with this diagnostic trouble code. Here is a list of the most common causes by car brands. Remember that these are only general guidelines, and you should make a diagnosis before replacing any parts. 1. Chevrolet.