Help; check engine light

[importcrew]

I need my Denali tested by the end of the month. I also need my sticker and we all know you can't get a sticker without passing the emission tests.

My problem is that my engine light is on.

Codes:
p0446 (evap vent system performance)
p0452 (fuel tank pressure sensor circuit, low voltage)
p0453 (fuel tank pressure sensor circuit, high voltage)


Anybody know what to do specifically? It'd be greatly appreciated. I'm planning on working on the truck tomorrow after work.

Click to read more...

 

[Oreif]

I could be a couple of things:
The "O" ring on your gas cap is cracked. (not sealing properly)
You didn't tighten the gas cap or it was loose at one point.
The sensor for the gas tank is bad or disconnected.

If the gas cap is/was loose, It takes 50 starts to clear it.
You could reset it but If I recall you need to drive it. Something about resetting the PCM resets the monitors and will cause an emission test failure.

 

[Bob Kazamakis]

Sounds like a gas cap or your solenoid. Get a new cap and dissconnect the battery. See if it comes back. Way to wait till the last minute!

 

[Just Yourshadow]

might be the fuel pressure sensor went bad but I would try the gas cap first.

 

[importcrew]

Well I always make sure the gas cap is tightened. The O-ring doesn't look bad but it doesn't hurt to try it out and change it. I have a feeling it's the sensor. Any way to test it?

As for waiting till last minute...well my connector wasn't working. I didn't know what was wrong with it at first and the engine light wasn't on for months upon months. It came on recently.

 

[Just Yourshadow]

ok I'm 98% certain it's your fuel tank pressure sensor. It's about 30 bucks and it sits right on top of your fuel canister so your going to have to drop the tank to get to it.

 

[importcrew]

Is there a way to test it?

 

[Just Yourshadow]

gas cap off, the voltage should be 1.5v or less.

 

[importcrew]

Alright. I'll check it out in a little bit and find out. Thanks for the help.

 

[Just Yourshadow]

brain fart moment, key on engine off when doing the test.

 

[Xtant12]

brain fart moment, key on engine off when doing the test.

I was going to say I had to do this on the GP and it was a small crack on the inner part of my gas cap. I didnt see it at first, I had to put water in it to see there was a crack..

 

[importcrew]

brain fart moment, key on engine off when doing the test.

I figured as much. I actually replaced my fuel pump about 1.5 years ago. I wouldn't figure it'd give me a problem this soon.

 

[Turbocharged400sbc]

I figured as much. I actually replaced my fuel pump about 1.5 years ago. I wouldn't figure it'd give me a problem this soon.

i've had some vehicles where the evap tubing rubbed through above the tank after fuel pump replacment

i hope ya werent lazy lol

 

[importcrew]

So here's the update. Took everything off the fuel tank. The problem was a damn wire. Some how it was cut. So I fixed it up, erases the codes. And everything is good now