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Diagnostic Code P0440 "HELP"

Diagnostic Code P0440 "HELP"

Postby duane4238 [OP] » Oct 01 2010, 12:57am

I have a '98 Silverado Ext Cab with a 305 engine and Auto Trans. Today, the check engine light came on and when I checked the code, it came back as P0440. That's an Evap. Emission Control Leak (small). So I figure there's a vacuum leak in the emissions system somewhere. I checked the gas cap to make sure it was tight, replaced the PCV valve and also the hose that attaches to the PCV valve. Anything else I should check or replace? I don't know where else to look or how to go about checking anywhere else. Any Ideas would be really appreciated, especially if you've dealt with the same problem. My truck has almost 180,000 miles, always use synthetic oil, and this is the first time I've ever had it throw a code. HELP! :o
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Re: Diagnostic Code P0440 "HELP"

Postby mbreener » Oct 01 2010, 1:15am

Most of the time that code is a bad or missing fuel cap... I would look to see if 1) it's there and 2) it's tight. Also possibly check the filler neck for cracks
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Re: Diagnostic Code P0440 "HELP"

Postby duane4238 [OP] » Oct 01 2010, 1:25am

Thanks for the suggestion. I used #600 sandpaper on the filler neck lip and put a new gas cap on this morning. It hasn't thrown the code yet, today, so maybe that did it!
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duane4238
Combustion on 1 piston [L2]
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Re: Diagnostic Code P0440 "HELP"

Postby lzn197 » Oct 01 2010, 1:46am

Usually for the vehicle to actually "run" the diagnotic check for P0440, the fuel level must be between 1/4 and 3/4 tank. Please keep that in mind. I would double check the filler neck for any leaks.
Gordon
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Re: Diagnostic Code P0440 "HELP"

Postby duane4238 [OP] » Oct 01 2010, 1:59am

Gordon,
Thanks for the quick reply. I will check the fuel neck first thing in the morning. I guess a close visual check is about all I can do. I'll also check the hose clamps on the neck, too.
Original Poster
duane4238
Combustion on 1 piston [L2]
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Joined: May 07 2010, 10:09pm
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Make/Model: Chevrolet Silverado
Extra Info: 5L 4x4 Z71 Ex Cab
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