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The Dude
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Discussion Starter · #1 ·
Well, today the engine light came on. I called Onstar to see what great help they might be. They said it was an Evaporative Emissions "issue" and he said to check the gas cap. I re-secured the gas cap and went on with my day. Tonight after work the light was still on so I called Onstar back to make sure it was the same thing, and it was. I asked the lady if there was a code associated with it and there was, but they are only able to give that out to dealerships, and GM techs :pissed: . I did a search and found some info, and one thing was a clogged vent line would cause the light and would also cause problems when filling the tank. When I do get gas, the pump shuts off all the fucking time and it pisses me off. I have to hold it a certain way and not pump full bore. I thought it was just a shitty design, but I'm beginning to think the problems are related. I plan on going to Autozone and get the real code. I will get back with those but if anybody has any suggestions, I'd like to hear them.
 

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Unhook your negative battery cable. Usually once your vehicle throws a code the light won't go away until the code is cleared out. This can be done with certain code readers or by disconnecting the battery cable for 30 or so minutes.

My truck just threw a code yesterday and i took it to advance to have it read. They even printed me off a list of what codes it threw. Mine happened to be a bad o2 sensor. I replaced both but the code was still there because it hadn't been cleared. Disconnected the battery for a little while and all was good.

In regards to your actual problem the only to really do it find out what codes it is throwing and post back up or get under the truck and start inspecting the evap equipment back near the gas tank. I think on your body style the evap canister and all that is back right in front of the gas tank. Check the hoses to make sure none are cracked or punctured.
 

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Jason RIP
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I've had this same code for a while, it is right next to the code for the gas cap not being on/or tight ... I havent had any problems, but I would like to eventually make it go away. The Evaporative Canister is sitting on top or to the side of the gas tank I do believe it has like a charcoal filter and vents teh fuels system.
 

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The Dude
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505 Posts
Discussion Starter · #4 ·
I figured it was back there somewhere, and I was going to crawl under it today, but it was raining. I'm going to Autozone tomorrow to have it scanned and cleared if it will, and go from there. Hopefully it was just a cap issue and I've since resolved it, but that's honestly not the way my luck usually turns out. Bill, love the Avatar, Jurassic Fart is one of my all time favorite things to watch to cheer me up, can't help but to laugh my full ass off. Thanks to both of you for your input. I've never dealt with this problem before.
 

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most of the time on the newer style trucks its the evap vent valve that is the problem. if your vent valve is messed up it will cause a problem when filling also make sure you have the ing off when filling. we have had ton of people complain about the pump shuting off when filling just to find out they leave the ing on to listen to the radio or something like that when filling up the gas tank. if your truck is a 04 the vent valve should be at the rear of the tank on the out side near the drive shaft. its a round little canister with a line going off of it o the evap canister which is up towards the front of the tank.
 

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The Dude
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505 Posts
Discussion Starter · #6 ·
Well, I did make it to autozone and had it scanned. Dude said there was a small leak in the gas cap. Cleared the code, put on a new cap and so far so good. That was Friday and I've been running around all weekend with no light. Hopfully it will stay that way. I still need to look into the vent thing given my frustration at the pump. Thanks to all.
 

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well i hope he was right because there was no way for him to tell it the gas cap was leaking from the code. the caps do sometimes leak but so do a lot of other things. do you happen to know the code?
 

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The Dude
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505 Posts
Discussion Starter · #8 ·
No, he didn't give me the code. But I did go to the dealership to buy a gas cap on monday and they are on factory backorder due to problems I assume. One of the mechs there told me it was a very common problem.
 

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i get the same thing..the code i get is P0442 evap leak (small). i am going the change the gas cap first and see what it does. its possible if it isnt sealing correctly or venting it can throw this code. maybe google that code and see if you find any related symptoms.
 
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