P0446

2003 PONTIAC GRAND PRIX
163,000 MILES • 3.1L • 6 CYL • FWD • AUTOMATIC
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DELPHN.C.
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Replaced evap. Vent valve solenoid and ECM. And gas cap.checked with a evap smoker. Still a problem. Question is, is there a Can bus module on this car.
Apr 20, 2016 at 3:27 PM
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HMAC300
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it's a blocked vent line someplace in system it needs to be smoke tested in order to fix this.
Apr 20, 2016 at 3:38 PM
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DELPHN.C.
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I have already smoke tested. Cleared the vent line.pulled down gas tank to check all lines and conections.checkEd evap filter. Made sure it was clear.
Apr 20, 2016 at 3:45 PM
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HMAC300
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how about vent line to tank?is the vent link kinked or pinched? does solenoid operate
Apr 20, 2016 at 4:22 PM
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DELPHN.C.
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Vent line to tank is open. Replaced solenoid and checked it.
Apr 20, 2016 at 4:25 PM
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HMAC300
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from the factory the evap system is checked with 3 psi air pressure. try applying that much and see if one of the hoses isn't opening and maybe soft and collapsing. other than that I don't know what to tell you, especially since you smoke tested it and replace solenoid. unless it's a connection or pcm problem which you can check with an ohm meter.
Apr 21, 2016 at 6:03 AM
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STRAILER
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Here is an article with video to show you how to fix it

https://www.2carpros.com/articles/evap-system-code-repair

Let me know what you find


Apr 21, 2016 at 6:55 PM
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ROBERT MANN
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I had the same problem with a 2001 chev impala to fix it I had put a little form a gasket on the evap lines at the engine the small o ring inside evap line no good put form gasket on inside line with Q tip and on pipe now no more p0446 done to a couple of autos work good for all of them.
Aug 30, 2016 at 8:55 PM
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ROBERT MANN
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THE O RING DOES NOT SEAL AS TIGHT AS NEW SO TRY FORM A GASKET TO SEAL THE EVAP LINES AT INTAKE SHOULD HELP FOR THAT CODE P0446
Aug 30, 2016 at 9:00 PM
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STRAILER
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You can try a new line or a larger is diameter O ring. The system must be air tight.
Aug 31, 2016 at 9:29 PM