Evaporative emission system purge flow performance during boost

The air/fuel vapor mixture continues through the EVAP purge pipe and EVAP purge valve into the intake manifold to be consumed during normal combustion. The EVAP system requires the PCM be able to detect a leak as small as 0.040 inch in the EVAP system. The PCM uses several tests to determine if the EVAP system is leaking.

Evaporative emission system purge flow performance during boost. EVAP emission canister purge is contolled by a valve which allows engine vacuum to pull stored fuel vapors from fuel tank into the engine to be burned, rather than be vented to atmosphere. A vacuum switch is used to detect when flow exists. If the PCM commands purge and sees that the switch is closed (indicating no detected purge flow) P0441 is ...

Both check valves create a contained system that allows purge flow in all operational circumstance, but no cross contamination of boost or vacuum, sort to speak. ... It was my goal to find the operational endpoints of the ECU's evaporative emission strategy while also fixing the boost leak to improve drivability performance and pull the turbo ...

Nonetheless, both definitions have the same basic meaning, which is that code P0497 is set when the PCM (Powertrain Control Module) detects an EVAP (Evaporative Emissions Control) system purge flow rate that is lower than expected. The purpose of the EVAP system is to capture, contain, and carry fuel vapors to the engine to be combusted before ...EVAP System Purge Flow Performance During Boost: No Sub Type Information: GO to Pinpoint Test HX: PCM: P1450:00: Unable to Bleed Up Fuel Tank Vacuum: No Sub Type Information: ... or using the hydrocarbon emission analyzer to determine an evaporative emission system leak is not recommended.OBD II fault code P0497 is a generic code that is defined as "Evaporative emission (EVAP) system -low purge flow", or sometimes as "Evaporative Emission System No Flow during Purge", depending on the manufacturer, and/or the source consulted. Nonetheless, both definitions have the same basic meaning, which is that code P0497 is set when ...paper deals with the less familiar evaporative emissions system and the controls used to reduce evaporative emissions. In it are de-scribed the system itself, the charcoal canister in which the emis-sions are stored, and a self-regulating heater which has been developed to improve the overall performance of the system. TheInadequate purge flow rate triggers which DTC? a. P0440 b. P0446 c. P0300 d. P0440 or P0446. ... All of the following can increase the pressure in the evaporative emission control system except _____. Choose matching term. ... A small leak is detected by the evaporative emission control system monitor that could be caused by a loose gas cap ...

Anyway, I've got a P2421 code that keeps popping (Evaporative Emission System Vent Valve Stuck Open), and I've read that the purge valve has an internal o-ring that can dry out and leak, causing failure. The problem is that I can't find the darn thing on my XC90 V8. The automobile fault code P144C indicates a problem with the Evaporative Emission (EVAP) system. The most common symptom is the Engine Light being ON or the Service Engine Soon Warning Light. The cause of this fault code is a stuck open EVAP canister purge check valve or a damaged EVAP canister purge check valve. Check engine light came on in the Girlfriends 2007 Outlook. Code P0496, " Evaporative emission system high purge flow" As best as I could search this forum and Google, I am going to replace the Purge solenoid. Problem is I do not know where to look on the car for this part.. Somehow NAPA had 1 in stock, so I plan to fix it this weekend.An incorrect P0441 code could indicate a faulty purge solenoid, a short circuit in the feed circuit, or a faulty PCV stuck in the feed circuit. A diagnostic trouble code (DTC) P0441 – Evaporative Emission Control System Incorrect Purge Flow is also known as an engine fault code. When it comes to Toyota fault codes, this is a pretty scary title.Programing Online PCM Land Rover Evoque L538! P144C Evaporative Emission System Purge Flow Performance During Boost DUY DUC WORKSHOP By DUY DUC WORKSHOP Facebook, Fits Range Rover 03 to 05 V8 PETROLThe EVAP purge solenoid valve controls the flow of vapors from the EVAP system to the intake manifold. The purge solenoid valve opens when commanded ON by the ECM. ... the purge tube between the EVAP purge solenoid valve and the EVAP canister to prevent pressurization of the EVAP system under boost conditions. Note that the presence of this one ...The description can be found in the EVAP (Evaporative Emission) system (See page ). MONITOR DESCRIPTION. The two monitors, Key-Off and Purge Flow, are used to detect malfunctions relating to DTC P0441. The Key-Off monitor is initiated by the ECM internal timer, known as the soak timer, 5 hours* after the ignition switch is turned off.

The EVAP system requires the PCM be able to detect a leak as small as 0.040 inch in the EVAP system. The PCM uses several tests to determine if the EVAP system is leaking. P0496 Ford Code - Evaporative Emission System High Purge Flow.Pump down to 20" vacuum and make sure it will hold for about 30 seconds. If the vacuum doesn't hold then there is a leak in the line going to the purge valve or the purge valve is bad. 5. Reconnect the vacuum hoses with their spring clamps. Reattach the throttle cable (if applicable) and replace the engine cover.Here is a list of the codes I have now: P0442 - Evaporative Emission (EVAP) System Small Leak Detected. *P0449 - Evaporative Emission (EVAP) Vent Solenoid Control Circuit. P0445 - Evaporative Emission Control System Purge Control Valve Circuit Shorted. *P0496 - Evaporative Emission (EVAP) System Flow During Non-Purge.P144C Definition: EVAP Purge Check Valve - Performance. The EVAP purge valve pulls fuel vapor from the gas tank and sends it into the intake manifold. From there, it burns off cleanly. Your Ford's PCM performs a test on the EVAP check valve during light boost conditions, one time per drive cycle.Definition Meaning Causes Fixes for a Hyundai P0441 Diagnostic Trouble Code: Evaporative Emission System Incorrect Purge FlowCauses of a Hyundai P0441 Code:B...In this video I bring you along as I diagnose and fix the classic P0496 that seems to plague these Buick Enclaves and Chevy Traverse's. A failed purge soleno...

Matthew frazier obituary.

The P144C is an engine code that indicates a problem with the vehicle’s EVAP System. EVAP stands for Evaporative Emission Control System and is one of many emission control systems installed in vehicles. The main components of the EVAP system are the purge valve, EVAP canister, hoses and vents, leak detection pump, fuel …P0441 Evaporative Emission System Incorrect Purge Flow; P0442 Evaporative Emission System Leak Detected (small leak) P0443 Evaporative (EVAP) Emission System Purge Control Valve Circuit ... P1441 EVAP System Flow During Non-Purge Condition; ... P2263 Turbo/Supercharger Boost System Performance; P2270 O2 …Diagnosis and Testing. Lincoln Navigator 2018-2024 Workshop Manual / Engine / Evaporative Emissions - 3.5L EcoBoost (272kW/370PS) / Evaporative Emissions. Diagnosis and Testing. Diagnostic Trouble Code (DTC) Chart. Diagnostics in this manual assume a certain skill level and knowledge of Ford-specific diagnostic practices.Evaporative Emission System Incorrect Purge Flow Actuator Stuck On. Leak detection pump creates negative pressure (vacuum) in EVAP system and EVAP system pressure measured. Reference pressure is measured at start and at end of leak check. If stabilized pressure higher than [second reference pressure x 0.2], ECM determines that purge VSV stuck open.The ECM has detected pressure in the EVAP system during a non-purge condition. P0496 Mercedes-Benz Description. The evaporative emission (EVAP) control system limits fuel vapors from escaping into the atmosphere. Fuel tank vapors are allowed to move from the fuel tank, due to pressure in the tank, through the vapor pipe, into the EVAP canister.

3. Replace the Purge Valve. If the EVAP system is functioning properly, the P0496 code can be caused by a faulty purge valve. The purge valve controls the flow of fuel vapors from the EVAP system to the engine. If the valve is stuck open or closed, it can cause the P0496 code. Replace the purge valve with a new one to solve the problem. 4.Purge volume is related to air intake volume. Under normal purge Conditions (non-closed throttle), the EVAP canister purge volume control solenoid valve is open to admit purge flow. Purge flow exposes the EVAP control system pressure sensor to intake manifold vacuum. SYSTEM DESCRIPTION: This system controls flow rate of …Yes, P0440, P0441, and P0446 codes are all related to the evaporative emission control system in a Toyota Prius. The P0440 code indicates a general issue with the system, while the P0441 code signals a problem with the EVAP system's purge flow, and the P0446 code is related to vent control issues. While these codes are distinct, they all ...The P0441 code, indicating an issue with the Evaporative Emission Control System’s purge flow, may have minimal symptoms, but its diagnosis and repair are crucial to prevent further damage to the vehicle and ensure compliance with emissions standards. By following the proper diagnostic and repair steps, it is possible to resolve the P0441 ...The fuel tank pressure (FTP) sensoris part of the evaporative emissions or EVAP system. It monitors pressure to detect evaporative leaks and loose/faulty gas caps that may be preventing fuel vapors from being contained in the EVAP system. Such leaks may result in decreased fuel efficiency, an increase in emissions, and decreased engine performance.Summary. The evaporative emission control (EVAP) system traps fuel vapors in a vapor canister, preventing them from being released into the atmosphere. EVAP systems can leak after some time. Depending on the size of the leak, the powertrain control module (PCM) can store a few related diagnostic trouble codes (DTCs).The evolution of evaporative emissions systems has been driven by changes in emissions standards. While some vehicle manufacturers have introduced very different designs along the way, Ford has primarily used a vacuum-based design as a foundation. The exceptions are its hybrid electric vehicles, which use an evaporative leak check …The EVAP canister purge check valve test is performed during minimal boost conditions, once per drive cycle, when entry conditions are met. The DTC is set if …P0441 Definition: EVAP System - Incorrect Purge Flow Here's the definition of P0441 for the Audi A3. It’s a generic diagnostic trouble code, which means regardless of what auto manufacturer built the vehicle, it’ll have the same meaning. It indicates that there is an issue with the Evaporative Emissions System. It'll often appear with

The powertrain control module (PCM) of a vehicle constantly monitors the performance of the EVAP system. It triggers the P0497 engine code when it monitors a low purge flow in the EVAP system. This article explains the P0497 code meaning, causes, symptoms, and how to fix it. P0497 Code Definition. P0497 Code – Evaporative Emission System Low ...

The description can be found in the EVAP (Evaporative Emission) system (See page ). MONITOR DESCRIPTION. The two monitors, Key-Off and Purge Flow, are used to detect malfunctions relating to DTC P0441. The Key-Off monitor is initiated by the ECM internal timer, known as the soak timer, 5 hours* after the ignition switch is turned off.If the PCM detects a failure during the intrusive test, a purge system performance fault is set (P0441). PURGE FLOW MONITOR IN BOOST: Turbocharged engines purge while the engine is in boost. This is achieved by having additional purge hoses and Hardware. The Boost purge monitor is used to check that this part of the …Web code p144c, evaporative emission system purge flow performance during boost. 91355 views 6 replies 5 participants last post by deceptivecode,. The Fault Codes Were P018C Fuel Pressure Sensor B Circuit And P144C Evap System Purge. Web repair information for p144c ford code. F150ecoboost.net is the best ford f150 ecoboost …This connects the Evap system via the schrader valve on the line between the purge valve and the solenoid. The tool induces both smoke and pressure up to 1 psi. There is flow gauge on the tool that monitors the pressure in the system to note if there is a leak or not. If there is leak, the smoke induced into the system can be used to find it.P0441 is an OBD-II diagnostic trouble code that indicates a malfunction in the evaporative emission control system and the purge flow. ... Evaporative Emission System Incorrect Purge Flow Code. by Alex Turner 12/04/2023. ... OBD-II stands for On-Board Diagnostics and is a system that monitors the performance of a vehicle's engine ...I have a 2009 XC90 3.2. The check engine light just turned on; I read the DTCs and got P0441 Evaporative emission control system incorrect purge flow. A Google search suggests that it could be several things including the purge valve / solenoid, charcoal canister, a leak in the vacuum lines connecting these components, or a loose gas cap.The EVAP purge valve is used to control the purge flow from the EVAP canister during engine running conditions. ... is used on turbocharged engines to create a vacuum in the EVAP purge line from the EVAP purge valve to the intake air system. During boost conditions, boost pressure flows through a venturi inside the EVAP ejector creating a ...If the PCM detects a failure during the intrusive test, a purge system performance fault is set (P0441). PURGE FLOW MONITOR IN BOOST: Turbocharged engines purge while the engine is in boost. This is achieved by having additional purge hoses and Hardware. The Boost purge monitor is used to check that this part of the Evaporative emissions system ...

2008 honda accord brake light stays on.

Aydan albuquerque reviews.

Labor: 1.0. To diagnose the P0496 Cadillac 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.Service Procedure. Visually inspect and push and pull on each of the following EVAP connections to verify a proper connection: Vapor line connections to the vacuum port side and pressure port side of the ejector. Refer to Figure 1 for 3.5L and Figure 2 for 2.7L. Vapor line connection at the port on air intake system (AIS) duct at throttle body ...This is what the EVAP system does and it does it using vacuums. If the car detects that there is flow in the EVAP system when there is not supposed to, it means there is likely a leak in the system that is releasing this hazardous fumes. ... This issue is most commonly caused by a faulty purge solenoid valve. You can only be sure if you have an ...Go to Step 2. Go to Diagnostic System Check - Vehicle. 2. Disconnect the purge pipe from the evaporative emission (EVAP) canister purge solenoid valve. Install a hand held vacuum gage to the EVAP canister purge solenoid valve purge port. Disconnect the EVAP canister purge solenoid valve harness connector.In this evaporative emission (EVAP) control system, purge flow occurs during non-closed throttle conditions. Purge volume is related to air intake volume. Under normal purge conditions (non-closed throttle), the EVAP canister purge volume control solenoid valve is open to admit purge flow. Purge flow exposes the EVAP control system pressure ...If the PCM detects a failure during the intrusive test, a purge system performance fault is set (P0441). PURGE FLOW MONITOR IN BOOST: Turbocharged engines purge while the engine is in boost. This is achieved by having additional purge hoses and Hardware. The Boost purge monitor is used to check that this part of the …The evap system high load purge line can impact vehicle performance by affecting fuel economy and engine efficiency. The purge line is responsible for directing excess fuel vapor from the evaporative emissions control system back into the engine for combustion. During high load conditions, such as accelerating or climbing hills, a large amount ...Re: Code P1441 Evaporative Emission System Flow During Non-Purge (torqueman2002) I had this same type code thrown on my 99 Chevy Silverado. Friend of mine who used to be a GM mech told me to replace the gas cap and the code would go away in about 2 weeks.The P0443 code is a diagnostic trouble code (DTC) that indicates a malfunction in the evaporative emission control system (EVAP). Specifically, the P0443 code indicates a problem with the purge control valve circuit, which is responsible for controlling the flow of fuel vapors from the EVAP canister to the engine intake manifold. ….

Powered by. Ask your car question. * All fields required. The 2015 Ford Escape has 1 problems reported for evap purge valve, emissions canister. Average repair cost is $1,200 at 40,150 miles.The P0443 engine code is triggered due to one or more of the following causes: A bad purge control valve. The wires of the purge control valve are damaged. Loose electrical connections of the EVAP system. Bad vent valve solenoid. Damage in the EVAP system. An issue with the charcoal canister. Damaged gas cap. Powered by. Ask your car question. * All fields required. The 2015 Ford Escape has 1 problems reported for evap purge valve, emissions canister. Average repair cost is $1,200 at 40,150 miles. Refer to DTC P0451 - Evaporative Emission Control System Pressure Sensor Range/Performance . STEP 3. Using scan tool (M.U.T.-IIISE), check actuator test item 4: Evaporative Emission Purge Solenoid ON.hunaink Discussion starter. 77 posts · Joined 2016. #1 · Jun 28, 2016. Hey guys, So my check engine light just came up and upon further investigation the car is throwing out a P0441 code. Any ideas what this could be? There has been a slight rumble coming through the exhaust & i have suspected the car of running rich. The code P0441 means that the Evaporative control system purge flow is incorrect. The Evaporative control system (EVAP) prevents gasoline vapors from the fuel tank from escaping into the atmosphere. The EVAP system catches and stores gasoline vapors in a small box installed near the fuel tank called charcoal canister. P0326: Knock Sensor 1 Circuit Range/ Performance (Bank 1) P0441: Evaporative Emission System Incorrect Purge Flow ... recommended that the Midtronics GR8-1299 system be used in ECM mode during charging. DO NOT connect any other battery charger to the vehicle during ECM upgrade.This evaporative emissions system purge flow sensor is designed to match the fit and function of the original sensor on specified vehicles, and is engineered for durability and reliable performance. This part is compatible with the following vehicles. Before purchasing, enter your vehicle trim in the garage tool to confirm fitment. Evaporative emission system purge flow performance during boost, These systems are designed to store and dispose of fuel vapors before they can escape into the atmosphere. A typical system consists of a small canister full of charcoal, valves, hoses, vents in the fuel lines and a sealed fuel tank cap. When fuel evaporates inside the gas tank, the excess vapors are transferred to the charcoal canister., This code only appears on vehicles that have a purge flow sensor or a leak detection pump. Early OBD2 Ford Rangers with non-enhanced EVAP systems simply had a small thermistor in the purge flow line that reported purge flow. Toyotas and Dodge vehicles with Leak Detection Pumps (LDP) measure system pressure changes to determine purge flow valve ..., The code P0441 means that the Evaporative control system purge flow is incorrect. The Evaporative control system (EVAP) prevents gasoline vapors from the fuel tank from escaping into the atmosphere. The EVAP system catches and stores gasoline vapors in a small box installed near the fuel tank called charcoal canister., 20% off orders over $100* + Free Ground Shipping** Eligible Ship-To-Home Items Only. Use Code: AZSPRING24, The fault code P0497 in an automobile can be caused by a faulty Purge Control Solenoid Valve (PCSV), an open or shorted PCSV harness, or a poor electrical connection in the PCSV circuit. To fix this issue, visually inspect the wiring harness and connectors, checking for any damage or broken, bent, pushed out, or corroded pins in the connectors., Service Procedure. Visually inspect and push and pull on each of the following EVAP connections to verify a proper connection: Vapor line connections to the vacuum port side and pressure port side of the ejector. Refer to Figure 1 for 3.5L and Figure 2 for 2.7L. Vapor line connection at the port on air intake system (AIS) duct at throttle body ..., 2018 2.7L F150 XLT with 20k miles on it. CEL came on last Friday throwing code P144C. “EVAP SYSTEM PURGE FLOW PERFORMANCE DURING BOOST”. Took it to the dealer and they suggested reprogramming the PCM per the TSB for the 3.5L. (Mine was made at the KC plant during the time periods for the TSB)., P0496 code definition. This is a generic code and it applies to all makes of vehicle, however, it does seem to be more prevalent in vehicles that come from GM. It means there is an issue with the purge flow in the evaporation system. Those who have Mazda, Kia, Hyundai, Honda, and Acura will find that the code’s description is slightly different., The purge valve solenoid is faulty. Insufficient vacuum supply to the EVAP system. There is an open or short in the voltage feed circuit to the purge valve solenoid. The Purge Flow Sensor or Leak Detection Pump has failed. There is corrosion or electrical resistance in the purge valve connector. The above are the more common causes of the ..., P0441 is one of the more common OBD II codes that can occur in the Dodge Journey . It is frequently caused by a loose or bad gas cap, cracked or disconnected EVAP system hoses, vacuum leaks, or a bad purge valve. Always start by taking a look at the gas cap. P0441 is related to the evaporative emissions control system (EVAP) and should not be ..., Powered by. Ask your car question. * All fields required. The 2015 Ford Escape has 1 problems reported for evap purge valve, emissions canister. Average repair cost is $1,200 at 40,150 miles., 2019 Ford Edge OBD2 Code P0496 EVAP Flow During A Non-Purge Condition. Top Cars; ... P0441 Evaporative Emission System Incorrect Purge Flow; P0442 Evaporative Emission System Leak Detected (small leak) P0443 Evaporative (EVAP) Emission System Purge Control Valve Circuit ... P2263 Turbo/Supercharger Boost System Performance; P2270 O2 Sensor ..., The Ford P144C trouble code means you have a “Evaporative emission system Purge Check Valve Performance” issue. The PCM performs an EVAP check …, Powered by. Ask your car question. * All fields required. The 2015 Ford Escape has 1 problems reported for evap purge valve, emissions canister. Average repair cost is $1,200 at 40,150 miles. , What does incorrect purge flow mean? Diagnostic trouble code (DTC) P0441 stands for "Evaporative Emission Control System (EVAP) Incorrect Purge Flow.". Your car's computer will set the code when it determines there's an improper amount of fuel vapor being "purged" from the EVAP charcoal canister into the engine., Labor: 1.0. To diagnose the P0496 Cadillac 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., This Rover came in with Evap system fault P144C (Evaporative Emission System Purge Flow Performance During Boost) from a Car dealer that we service a lot of their …, Whenever a device performs an EVAP system self-test, it closes off the system and opens the purge valve. To calculate the purge flow, the computer uses the gas tank pressure sensor to determine ..., One of the primary consequences of a stuck closed purge valve is the increase in pollutant emissions. The purge valve is responsible for controlling the flow of fuel vapor from the charcoal canister to the engine, where it is burned off. When the valve gets stuck closed, it restricts this flow, causing a buildup of fuel vapor in the canister., Programing Online PCM Land Rover Evoque L538! P144C Evaporative Emission System Purge Flow Performance During Boost DUY DUC WORKSHOP By DUY DUC WORKSHOP Facebook, Fits Range Rover 03 to 05 V8 PETROL, The powertrain control module (PCM) continuously observes the EVAP system performance. When your EVAP system experiences an issue with the purge flow, the …, Code P0441 KIA Description. The Engine Control Module (ECM) tests the Evaporative Emission (EVAP) system for the following conditions: - Large and small leaks. - Excess vacuum. - Purge flow during non-commanded conditions. - Fuel Level and Fuel Pressure sensor faults. - EVAP Purge and Vent Valve faults. The ECM monitors the Fuel Tank Pressure ..., Equip cars, trucks & SUVs with 2016 Ford Escape Canister Purge Valve from AutoZone. Get Yours Today! We have the best products at the right price., If the PCM detects a failure during the intrusive test, a purge system performance fault is set (P0441). PURGE FLOW MONITOR IN BOOST: Turbocharged engines purge while the engine is in boost. This is achieved by having additional purge hoses and Hardware. The Boost purge monitor is used to check that this part of the Evaporative emissions system ..., The fault code P0497 in an automobile can be caused by a faulty Purge Control Solenoid Valve (PCSV), an open or shorted PCSV harness, or a poor electrical connection in the PCSV circuit. To fix this issue, visually inspect the wiring harness and connectors, checking for any damage or broken, bent, pushed out, or corroded pins in the connectors., The ECM has detected pressure in the EVAP system during a non-purge condition. P0496 GMC Description. The evaporative emission (EVAP) control system limits fuel vapors from escaping into the atmosphere. Fuel tank vapors are allowed to move from the fuel tank, due to pressure in the tank, through the vapor pipe, into the EVAP canister., It means that there is an issue with the Evaporative Emissions System. P0441: Evaporative Emission Control (EVAP) System → Incorrect Purge Flow. The vehicle’s ECM will trigger this code when it detects that the vacuum level in the Purge System is not within the proper specifications. If this code is thrown, it can cause the vehicle to fail ..., In this video I bring you along as I diagnose and fix the classic P0496 that seems to plague these Buick Enclaves and Chevy Traverse's. A failed purge soleno..., The air/fuel vapor mixture continues through the EVAP purge pipe and EVAP purge valve into the intake manifold to be consumed during normal combustion. The EVAP system requires the PCM be able to detect a leak as small as 0.040 inch in the EVAP system. The PCM uses several tests to determine if the EVAP system is leaking., What the P0441 code means. P0441 will be seen when the ECU has detected incorrect purge flow in the Evaporative (EVAP) emission control system. When the purge flow is determined to be faulty, a Check Engine Light is set and illuminated on the dashboard. The ECM uses a vacuum switch to detect the purge flow from the EVAP canister., Programing Online PCM Land Rover Evoque L538! P144C Evaporative Emission System Purge Flow Performance During Boost DUY DUC WORKSHOP By DUY DUC WORKSHOP Facebook, Fits Range Rover 03 to 05 V8 PETROL, Definition Meaning Causes Fixes for a Hyundai P0441 Diagnostic Trouble Code: Evaporative Emission System Incorrect Purge FlowCauses of a Hyundai P0441 Code:B..., The PCM uses the purge valve to diagnose the EVAP system by keeping it open and the canister vent solenoid closed. This causes the fuel tank pressure sensor to determine whether or not a vacuum is present if the system is sealed. If the PCM detects that the EVAP system has flow when it shouldn’t, the computer will log a P0458 code.