Good ole P0446 code... If you read a little closer in the GM Tech manual you will see Its an evap perormance issue... It Does NOT ALWAYS mean that its the Vent Valve solinoid. The presure sensor on the Fuel pump and the sending unit in the pump are supposed to read predetermined values at different levels of fuel. If those values do not match up as the Evap system is opperating while the engine is running, It will set That code. Its telling you there is Performance issue with the system.

It could mean the Pressure sensor is not reading the proper value.

 

well we tested it and for sure its the sensor. but somerthing weird happen on friday.. since i was having problems with my sensor and ses light i had wheatly dis-able it..and all other sensors that went with this system i think.? but then i was getting a new code saying large leak in system and tighten gas cap. for about 2 months this has been happening. called wheatly i am supposed to meet up with to see what we can do. and friday on the way home the ses light turns off and no more tighten gas cap alert. all weekend i drove the truck eveywhere. no more light or alert??? this really has me thinking how did it correct itself? or am i missing something??? glad the ses light is off but for how long? anyone?

 

anyone??? has anyone ever have a ses light go off and not come back on.. its been on for i say 3 months or so. and then friday its off.. all weekend off and today off, filled up today also..? i am happy but i dont want it coming back on.. thanks

 

If he was able to dissable something through the tune Perhaps that is what's causing the other faliures to show up. Like the pressure valve is opening to pull vacum in the tank but the Vent solinoid is not closing to seal up the system... That would show a leak.... same as the pressure sensor not reading properly. It might show no presure in the tank and it thinks the gas cap is loose, venting the pressure that should be in there when you start the vehical up...

With out Physicaly testing every component It's hard to say 100% but that's my take on whats been happening.

Keep us posted... I am sure in alot of real dusty area's the vent solinoid cloging works but out here in California I have done 3 GM Vehicals with the P0446 code and it usually ends up being the pressure sensor. we do the Vent solinoid because of the early TSB from GM about them getting cloged but it usually comes back.

 

You sure it didn't burn out???

 

no because when i start the truck the light is on with others and then goes off like normal.. yea i figured by dis-ableing those other sensors is how my tighten gas cap came on but now what.. i never got a re-tune. just driving it hard on fri. on the way home and its off? weird if you ask me. lol

 

You may have an intermittent problem that has temporarily fixed itself...or it could be temperature related (it's gotten warmer here, how about by you?).

 

Maybe the Values Balanced out between the fuel level and the bad Pressure sensor...

 

whatever happen i am happy to see that light go off finally. lol.. and i did actually get the tighten gas cap code this morning. but no ses light...

 

Maybe the light is just tired of coming on... It must figure whats the point, he wont fix me any way... LOL