Unable to fill with gas

[demon71]

Check Engine light is on along with tighten gas cap msg, Got a new cap, Light went off and now back on, When I go to the pump I'm only able to get in 1/2 gallon then it stops and overflows. Dealer said it could be 3 things, Filler neck, Vapor Canister, Vent Valve, Anyone else have this issue?

 

[sumo]

whats the code?. Chasing evap leaks can be a pita

 

[nytahoe]

get the code and start from that

 

[Thumper8302]

damn seeing this post scares me.. i just found out i had the p0446 code... find out ur code man and let us know whats up

heres a quick lil reference

What does that mean?

Evap vent valve has only one purpose. It closes in order to seal the vent so the EVAP system can pressurize and ensure there are no leaks. Evap vent valve is usually supplied Batt. voltage with key on. The ECM's driver controls the ground, and when grounded, activates the valve (closing it). If the ECM detects a short to ground, and open,or a short to battery voltage on the control circuit, P0446 will set. Code also may refer to ECM detecting that EVAP system is unable to achieve or maintain vacuum during test.

Symptoms

There will be no obvious symptoms to driver, other than MIL illumination.

Causes

A code P0446 could mean one or more of the following has happened:

Faulty vent valve
Open, short or excessive resistance on Vent valve control circuit
Blockage of vent valve
Bad PCM
Possible Solutions

With a P0446 OBD-II trouble code, here are some things to try:

Replace Vent valve
Repair open, short, or resistance problem in control circuit
Repair open, or short, or resistance problem in power circuit
Replace PCM

Other EVAP DTCs: P0440 - P0441 - P0442 - P0443 - P0446 - P0453 - P0455 - P0456

 

[demon71]

code P0446 this is what i get

 

[Anthony]

Yup, I had this issue with first getting the "Tighten gas cap" message for a few months and replaced with 2 caps, then recently I was unable to fill the tank just like you. Then I went to Advanced Auto Parts and paid $28.00 and got this:

Here is what is it called and how to fix it:
AC DELCO 214-2149 [CANISTER PURGE SOLENOID VALVE]
Features:
Brand new AC DELCO component with correct connector
Replaces dealer part numbers: 25932571, 214-2149

-It started off as 'Tighten Gas Cap" on the DIC, As the solenoid valve was stuck open and would vent the tank so the computer thought the gas cap was loose. I got the solenoid unstuck but later it failed in the close position and would not vent when filling the tank. I too tried everything including turning the nozzle completely upside down but the nozzle would just click off. The day after I replaced it I was able to fill the tank as fast as the pump would go and the engine light went out a day or so later, Have not had the problem ever since.
****UPDATE****

-Problem seems to be solved, I replaced the evap solenoid the day before yesterday and now I can fill the tank as fast as the pump will go. It only cost me $28, The engine light has not shut off yet but that should resolve itself in a few days after I drive it around a bit.

-It connects to the charcoal canister under the rear by the gas tank, A lot of people refer to it as the evap valve or solenoid.
-You have to crawl under but its just above and infront of the rear axel.
-A screw driver to pry up on the tab in the middle of the bracket and the same with tabs on the hose to release it. Then slide the new part back in the bracket and bend the tab back to hold it and make the connections.
-About 15 minutes of your time and no gas leaking, Also easier to get to if you drop the spare tire.

 

[sumo]

nice hope that fixes ya

 

[ktmhans]

was just going to post about this same problem, had a really hard time getting gas in yesterday, like 1/2 gallon then shut off. then it started hard. also had the tighten gas cap come on 2 days ago. Guesse I'll add this to the list of shit for this thing this weekend. To all these NBS tahoe have all these problems or just the used one I bought?????????
Thanks to the previous posters!