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common code 0446

08-08-2017, 06:13 PM
I've been at this 2003 buick lesabre custom for two weeks on and off now.
Been working on cars more than 45 years and this puppy has me frustrated.
O446 code. 1st put new gas cap on, then pulled vent valve out, by the gas tank, applied 12 volt power and heard the clicking of valves opening and closing, cleaned all connections, checked vapor canister, blew thru it, no restriction, checked all hoses, cleaned all connections,followed lines to front where fuel and purged valve is. All connections good. Purge valve? applied 12volt power to it no clicks, from what I no a valve is in there and it should open and close at a certain engine temp, right? apply direct power might fool that purge valve is my thought. With key on, no power there mmm is there supposed to be?? number 11 fuse under rear seat is good. car runs super, starts great! does 65 in 4 seconds.
I am stubborn and like to no figure this out instead of putting a black piece of tape over the check engine light. ha thank you huey oh I did not check the sensor on top of the tank. 0446 means something is plugged I believe

Tech II
08-08-2017, 11:38 PM
This code has to do with the vent solenoid operation.......

A clicking solenoid is not a definitive answer.......when the system is sealed, the vent solenoid is powered and it should not leak....it can click but may still leak.....

A GM shop would perform a smoke test....pressurize the system with smoke and command the vent and purge solenoids closed......then pressure would be observed...if it drops, you look for the smoke....if you observe smoke coming from the vent solenoid, you check the harness for power and ground, and if ok, replace the vent solenoid....

08-23-2017, 09:56 AM
What kind of smoke? Sounds like a valuable test for those of us hanging on to the 3800.

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