Evap engine code

[pt1965]

first engine code at 170k miles. 'evap' according to o'reillys auto parts.
where should i start to investigate? my son says theres something similar to a pcv valve towards the rear of the engine to check?

 

[George B]

What is the actual DTC code number?

 

[pt1965]

What is the actual DTC code number?

i didnt actually see it and they didnt offer it. knew i should have asked!

 

[pt1965]

UPDATE! the code is P0442
in the few weeks that the engine light has been on i have seen the message pop up 'tighten fuel cap', but its not loose. do you think a new fuel cap will solve the problem? or is it really something else?

 

[OR VietVet]

Seems like every time we see threads about the "evap codes" the OP ends up replacing the evap system complete before it actually stays fixed.

 

[Rocket Man]

Ahhh the old familiar P0442. There’s 4 components plus the actual lines that could be at fault. You can try replacing them one at a time or go for all 4. I suggest using ACDelco parts. First you can try the fuel cap- if it leaks you will get that code. Then there’s the purge valve and vent valve. Purge valve is in the engine compartment, vent valve is next to the charcoal canister which is near the fuel tank. If those 3 don’t fix it, then it’s likely the charcoal canister itself in which case you’ll probably need to blow out the lines that go between these components with compressed air because the charcoal pellets get in the lines.

 

[pt1965]

i guess all this stuff is to protect the environment? so if you dont replace the parts,is it affecting fuel ecomomy or performance? looks like all 4 parts are about $160 on rock auto. i see the reason for replacing the 3 first, since the can is around $95. so, is there a possibility of replacing all and still get the check engine light? does the rabbit hole continue?

 

[Rocket Man]

Yes it’s for the environment, it keeps gas vapor from escaping into the atmosphere. Not sure if it will affect fuel mileage, I doubt it. I ended up replacing all 4. Some guys get away with 1 or 2. There’s is a way to check the components with a Tech2 but it’s a PIA. It’s not a complicated system, blowing out the lines if they get pellets in them is the last thing that could go wrong. If you don’t fix this issue eventually you will have a hard time putting fuel in the tank because it won’t vent so the gas nozzle constantly clicks off.

 

[OR VietVet]

Taking a chance on one or two parts replacements, IMO, is a crap shoot. The whole system is the same age. They work together to prevent the fumes/vapors release to the atmosphere. It is a PITA to get under there for some of that work. Do it all one time and likely have the problem solved.

Hell, I recently had a fog light go out. A new and an old one mixed showing at the front bothered me. I did both of them.