[mowerboy1000]

I just got a 2000 Sierra, and when I got it, it did not have the original gas cap. I went to the dealer and got a new one and it is throwing the check engine light and I was just wondering if anyone had this same proble with the original gas cap, or if anyone had a way to fix it

 

[ChevyFan]

Might have to do with the seal? Does the check enging light go on/off when you put the aftermarket cap on it?

 

[TrailLeadr]

These crazy gas tanks these days.

 

[ChevyFan]

Maybe they didn't provide the right cap? I know you can get an error if the tank isn't sealed right becuase there are different types of fuel-return lines that run on vaccuum, etc.

 

[TrailLeadr]

Yeah...like I said...

It's probably either the wrong cap, or a defective seal.

 

[84fiero123]

You did turn it down to the clicks, and then 4 more clicks, right?

You have to get those four clicks to properly seal the gas tank.

 

[mowerboy1000]

Yeah i clicked it a lot, I am going to reset the light then see if it goes off again with the cap that came on the truck and it the light stays off I am going to take the cap back to the dealer

 

[ChevyFan]

I'm interested in hearing how this turns out. Wonder if it justs takes a few cycles to get the code gone or if you can reset the computer if it will just go away.

 

[brownbomb]

I had the same problem with a 2000 Buick Regal. My check engine light was coming on so I took it in for service. $65.00 later they told me the gas cap had not been properly sealed (turned enough clicks to seal the vaccum system). Oddly this was not a warranty covered issued either. Appears warranties don't cover me being an idiot or gas caps being over engineered. Anyway the check engine light came on routinely over the next several years of my lease and would go off on if its own. Never took it back to the dealer except at lease turn-in....

 

[mowerboy1000]

I disconnected the battery and the light is still on so I am wondering if it is another problem, does anyone know what else it might be

 

[ChevyFan]

Did the light come on with the old gas cap?

 

[84fiero123]

You need to have the codes read.

You unfortunately have to have a code reader to get the codes out.

Most of the auto parts stores will read them for you.

Just plug it in and see what comes up. It may be anything.

 

[mowerboy1000]

It was off when I got the truck, and then I switched the gas cap and about 2 weeks later the light came on

 

[84fiero123]

It was off when I got the truck, and then I switched the gas cap and about 2 weeks later the light came on

Now that is a horse of a completely different color.

Get the code read, It doesn’t sound like it has anything to do with the gas cap.

 

[mowerboy1000]

i did it said
P0446
EVAP Emission
Control System
Vent Circuit Malf

And teh guy at the auto parts store told me that the gas cap could be the problem and sice the truck didn't have the original gas cap when I got it I just thought that me putting the original gas cap on might have caused the light to come on

 

[84fiero123]

Could also mean you need you evap canister replaced.

 

[84fiero123]

Or a vacume leak in the system.

 

[robotic_t]

gas cap problem

Is that the only code that comes up on the scanner, does the truck run o.k. or is there other symptoms that are related to this problem

 

[mowerboy1000]

The truck wouldn't start so I took it into the shop. The guy who owns the shop told me that I needed to take it to the dealer, because the transmission was also setting codes, and the code that had been previously set could be something else and they would let me know there. So I took the truck to the dealer. They told me that there were six codes that had been set and all of them in a way had to do with ignition switch. So It wasn't a problem with the gas cap at all, but the ignition switch. Which was a nice $300 plus a extra $150 to rewire my remote start.

 

[mowerboy1000]

Iwent to leave y girlfriend's house the other day and it wouldn't start again so back to the shop it goes, hopefully it is something simple, or the fuel pump, because the warrenty will cover that