So when I first bought the monte I threw on a locking gas cap, this code came up so I put the stock one back on. All is good until about 2 months the darn code pops up again, I scanned it with my obd scanner and it's shows 2 of the same p0440 codes I already checked for any broken or leaking lines, where do I start next? I know its many things that could cause the code to come on. I just don't want to start replacing things that don't need replacing and wastin money lol.
Any suggestions?

 

Could be your stock gas cap now.

There are many lines in the system that could have cracked, it's such a pain to diagnose this one.

 

Ahh crap lol

Will it cause any mechanical damage if it's not fixed? Lol
I'm considering getting a PCM from zzp, I can get the code removed permanently with that correct?

 

You could, but if there's a serious EVAP problem that would suck. Although you probably would smell the gas...

There are sometimes vents above the tank that can clog too.

I think they can smoke test the system and find the leak / clog

 

I personally would NOT have that code deleted from the PCM. I don't think it will cause mechanical damage, but it's still alerting you to a problem condition.
I believe a friend of mine had this code on a 3800 powered '97 Grand Prix. I replaced some dry rotting rubber vacuum couplings, cleared the code and it has not popped since.Below is info I pulled from the Internet.

Causes: A code P0440 could mean one or more of the following has happened:

• The gas cap is not installed or working properly
• The purge solenoid has failed
• The canister is plugged and not working properly

Possible Solutions:

With a P0440 OBD-II trouble code, diagnosis can be tricky at times. Here are some things to try:

• Remove and reinstall the gas cap, clear the code, and drive for a day and see if the codes come back.
• Inspect the EVAP system for cuts/holes in tubes/hoses
• Inspect for damaged or disconnected hoses around the Evap purge solenoid
• Check and/or replace the sensor
• Check and/or replace the purge valve
• Have a professional use a smoke machine to detect leaks

 

Did you forget to tighten ur gas cap all the way last time u filled up?

 

Well there's no gas smell, I already check all hoses for rotting and rips but all seems fine. I always tighten the gas cap correctly lol, I'm going to try a new gas cap and new canister purge valve (since those are the cheaper things to start with lol) I'll erase the code and hopefully it doesn't come back :p lol

 

OH, I don't remember for sure, but this might have been a code my wife's '01 Mustang got last year. The problem was holes in the filler neck! Ford covered the filler neck with wire loom and I think that held water and such right on the metal neck. Replacement neck was $150 (and came with fresh wire loom on the neck)!!!
I did NOT pay $150. Instead, as a first attempt, I removed the loom (left it off), cleaned up the debris around the neck and using POR15 and JB Weld, sealed the pin holes. The code went away on it's own after a couple of drives and has passed an emissions check since!
Granted, I doubt you have a rotted filler neck, but I found this a good story anyways.

 

Great story man
Good way to save some money lol

Will have to double check everything again later today when I have time

 

damn this P0440 code, i had it on my car for almost 18 months, every time i turn it off it comes back on a week later, i checked everything and anything that might cause a leak and i never found a thing, the filler neck was good, all the vacuum hoses where intact, i even checked the fuel lines and and every single hose under the car and under the hose even if it wasn't a vacuum hose, double checked my filler neck and the top of my fuel tank for holes or perhaps cracks but nothing. i even replaced the fuel cap with an original one from the dealer that didn't do squat. after a while i decided i'm tired of this yellow light on my dash and took it in for a smoke test, even the master tech couldn't find the damn leak..WTF!!! 6 months after the smoke test my (3-4 months ago) i replaced my brake booster and for some random reason the code went away 3 maybe 4 drives after the new booster was installed. turns out inside the booster itself was the leak, one of the vents (not sure what they're called) was cracked which caused a very, very slow leak that you couldn't even hear and since its sealed the smoke test never showed its location. hopefully that's not you're problem as the filler neck is usually the problem with this code in most GM cars....