1998 mercury mountainer code p0455 large leak what is the fix

Question edited for clarity. P codes for DTCs must have upper case P.

All questions need FULL 'year make model'.

White smoke is steam, and this is normal at this time of year and is mentioned on this website a LOT at this time of year. Gasoline has weather in it at molecular level and is burned off as steam.

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P0303 Misfire on Cylinder 3
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OBD-II Trouble Code - P0455

RepairPal.com https://repairpal.com > obd-ii-code-p0455
OBD-II code P0455 is a problem with an Evaporative Emission Control System Leak. Get expert information on fault code P0455.

P0455 Code: Evaporative Emission Control System Large ...

CarParts.com https://www.carparts.com > ... > OBD-II Trouble Codes
Aug 6, 2023 - Code P0455 is typically triggered when your vehicle's computer detects a large leak in the EVAP system. Symptoms of a P0455 include a lit check ... Videos

2:20
How to Fix P0455 Engine Code in 3 Minutes [2 DIY Methods ...
YouTube · nonda 2 minutes, 20 seconds
Oct 21, 2020

P0455 EVAP Large Leak Detected

Gas cap, leak detection pump, charcoal canister are all possible causes P0455 Ricks Free Auto Repair Advice

Vent hose for return fumes busted? Look under car for bad hose Steelseries Sx Professional Gaming Mouse Pad AmanStino

large evap leak --check gas cap that it is on --look under truck at rear of fuel tank by spare tire and check the evap canister and hoses the following link will assist you
https://www.obd-codes.com/p0455 How to Fix Check Engine Light P0455 Emissions Purge Valve Replacement How to Fix Check Engine Light P0455 Emissions Purge Valve Replacement

OBD-II Trouble Code: P0455 Evaporative Emission Control System Leak Detected (no purge flow or large leak)

Most people find it is from the gas filler cap. Here is a page where people discuss the problem and what they did:

http://www.jeepforum.com/forum/f9/engine-code-p0455-1051189/

P0455 is Evaporative Emissions System Leak Detected (Large) and means that there is a large leak in the system probably with one of the EVAP hoses near the fuel tank or EVAP canister or maybe even A leaky purge valve.

Google the codes

Lots to read & study

OBD2 PO401

OBD2 PO455

Think you will a repair shop to smoke the
Evap for the 455

p0455-- emission control system ( a large leak ) the most common cause is a bad seal on fuel cap, remove and replace cap, if light stats on. replace cap. if not the cap it could be any where in emission system. p0442 is--same as above. Code p0442 indicates a fuel vapor leak in the EVAP control system. To fix this problem, remove and reinstall the gas cap. Clear the codes and drive to see if the codes reappear. If the code appears again replace the gas cap or inspect the system for cuts or holes in the tube or hose. good-day !

The p0455 is for a leak concern and if that was the only code I'd say give the cap a shot. However the p0455 is most likely just a side effect of the P0449. The P0449 is a test that is run on the vent solenoid circuit to check the electrical functions in basic terms. The computer is putting out voltage amount X and in a properly functioning circuit it knows it will see voltage amount Y come back. It isn't coming back as what it expects to come back at so there must be something electrically wrong with the vent circuit. And of course if the vent doesn't work you get a large leak. If we are just throwing parts at trucks the logical one for you is a vent valve. Since your Vue is a 2008, most likely there is a good chance that it's covered under the emission warranty which is 5 years.
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