What do these Autozone Check Engine Scan codes mean?

Question

The nice fella at AutoZone just scanned my check engine light and here are the results: P0441: Evap Purge Flow Fault; P0446: Evap Emission Control System Vent Circuit Malfunction.

He basically explained that I should take the car on a long highway drive (been there, done that) or replace my gas cap -although we both agreed that my gas cap seems tight. All in all he said the light is not a big deal but my car will not pass inspection next year if the light's still on.

I'm just gonna buy a gas cap (and if that fails go to mechanic). But can anyone out there provide more insight into these codes and pinpoint what the problems might be?

Answer 1

Some times is hard to find a real reason for a P0441 because can be a leak fron the evaporative system, and need a special tool to find then, but believe or not the Autozone guy is right, some times the light go off after a long ride, 23 years working in a freaking cars, Ford dealer

Answer 2

OBD II enhanced evap monitoring works something like this. Left unchecked, fuel (gasoline) would evaporate out of your vehicle's fuel tank and pollute the atmosphere with harmful hydrocarbons (HC) (gasoline). To prevent this, vehicles are equipped with fuel evaporative control systems. Basically, instead of fuel vapors being allowed to escape from your car into the atmosphere, they're routed through hoses and tubes to an evaporative cannister. This cannister has charcoal in it. The charcoal traps the HC vapors storing them until they can be drawn into the running engine and burned (oxidized). When the vehicle is ready to purge the cannister, a purge valve is activated connecting engine vacuum from the throttle blade or plenum chamber (intake manifold) to the cannister. The vacuum draws air from the atmosphere and through the vent solenoid (EVAP Emission Control System Vent Circuit). The air is drawn through the cannister purging the HC vapors from the charcoal. The vapors now enter the engine where they are burned in the vehicle's combustion chamber.

I don't know what is specifically wrong with your car. If there is a problem with the vent solenoid it stands to reason the vehicle won't purge as designed.

Whichever of these codes appeared first will have "freeze frame data." Freeze frame data serves 2 purposes. One, it clarifies which problem appeared first since only the first code will have freeze frame associated with it. Secondly, it describes how the vehicle was being operated when the diagnostic trouble code (DTC) was captured in the vehicle's computer's memory. This helps technicians duplicate when the problem occured to assist in locating the problem and after repair, verifying the repairs were effective.

OBD II enhanced evaporative monitoring also checks the systems ability to hold pressure (leak check). A leaking system will allow harmful HC vapors to escape into the atmosphere. The most common source of leaks are loose or leaking fuel caps. Neither of the codes you described above suggest a leak problem.

Hope this helps.

Answer 3

make sure the gas cap clicks several times after installing it as yes that is most likely the problem. but the codes have to do with the emision control devices installed on your particular vehicle.
p0441 is a purge for the evaportive canister, i.e. where the gas tank fumes go to instead of the atmosphere
p0446 thats just a code telling you that there is a problem

make sure you click the gas cap several times but you also might have a bug thats gotten in somewhere

Answer 4

Get the Haynes manual for your car which is available at Autozone. It costs $12 to $14 and is worth its weight in gold. All the codes are listed as well as the laymen's term for what the issue is. There will be detailed diagrams instructing you in how to remedy the problem.

You can also buy the code reader at Autozone. I recommend this highly. Keep the reader and manual in your glove compartment, and you will never be ripped off or falsely diagnosed again.

p.s. Stay away from the stealership. They are the worst for taking your money. Anybody who says go to the dealer for repair is telling you to bendover.

Answer 5

I'm tired of running from mechanic to mechanic. None of them being able to help my check engine problem. You'd save yourself a lot of time money and heart ache by taking it directly to the dealer. It's their car, they should be able to help you out. I've learned a valuable lesson with my car, these side mechanics are hustlers, if you don't know them, they'll try to get you for all your cash, you might as well go to the source of the problem (dealer) good luck.