P0442 code question

laneo9417 said:

So I was cruising down the highway last night when the check engine light came on. I pulled into Autozone and borrowed their OBD tool and got the P0442 code. I’m thinking (and hoping) that this is just a gas cap/filler neck issue because the truck is idling fine with no noticeable changes in the ride. The gas cap is the original but the rubber seal looks fine (there are no cracks and it's not warped or anything) and it clicks and locks into place normally. The filler neck is also the original but it does have a decent amount of rust, including around the outside of the neck where the cap locks in. I’ve done a fair share of research on this topic this morning but I still have a couple questions because I have seen conflicting answers:

Can the code be cleared without an OBD tool, such as disconnecting the battery? I would like to try this first to see if I can get the check engine light to stay off (hoping it was just a loose gas cap that triggered the code).

If the check engine light stays on (or comes back on) would it be fair to say that a small crack or hole in the filler neck is to blame given the truck is running completely normal? I’ve seen filler necks for sale on 1Aauto and Rockauto fairly cheap, and they seem relatively easy to replace.

Any help is appreciated.

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laneo9417 said:

Appreciate the info. I'll try the petroleum jelly trick. If that isn't the cause how do I go about fixing this? I'm most likely going to get a new filler tube so do I clear the code first, install the new filler tube, then wait to see if the check engine light comes back on? Or will installing the new tube clear the check engine light automatically if indeed it is the cause?

Also, can the code be cleared without an OBD II scanner? I have been considering buying my own at Harbor Freight but if a battery disconnect can clear it then I may just stick with that.

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koda2000 said:

i think you should spend a little time trying to find the real problem. it might not be your filler neck. there's a line that goes to from your tank to the purge canister, located above the spare tire. there's a vacuum line that runs up to the engine compartment and goes to the purge solenoid, which is located under the battery. then there's a vacuum hose that runs to your intake manifold. a leak, or malfunction, anywhere in the evap system could be triggering your code. after checking your gas cap seal remove the filler neck and inspect it closely for any pin holes. i hate throwing money at a problem w/out determining what the issue is, but it's your money.

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bobflood said:

If you are going to do your own work, an OBDII scanner to read and clear codes has become a necessary tool. Go on eBay and Amazon - I found some basic ones last year that were only $10-15; I bought three and put one in each car. I also have a better one that reads data real time and provides some other capabilities - I use it all the time on my own and on friend's vehicles. Good luck.

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