Check Engine Light Due to Gas Cap Issue on Pontiac Montana

Problem Description and Possible Solution

Illumination of the Check Engine Light can be caused by a loose or worn gas cap.

Problem Data
RepairPal Verified
Average mileage: 129,443 (79,000–280,000)
10 model years affected: 1999, 2000, 2001, 2002, more2003, 2004, 2005, 2006, 2007, 2008
43 people reported this problem
Viewing 1 - 10 of 10 comments
Check has cap light came on then check engine. Put on a new gas cap fine for two weeks then started again . Bought a new gas cap and again both check gas cap and engine light is on two weeks later.
Engine light is on and the 2006 Montana cuts off when I put my feet on the gas. It one thing after another. I bought the truck a year ago and it's horrible on gas. I'm going to tradeit in.
I have had to replace my gascap several times over the last few years. It gets frustrating and expensive.
Not gas cap. I live in Ontario Canada and vapour return tubing was rusted where it passes thru the LH rear wheelhouse to connect to fuel filler tube. Look under the plastic baffle in the wheel house and you'Ll find it covered by dirt and salt.
Quick fix for me was to buy a new filler tube from the dealer -in stock so it must be a common problem. Two hose clamps and you are done. Not the cheapest but a lot less hassle than trying to find solid tube to clamp to a piece of hose to. Would probably have to pull tube out anyway.
Remember SAFETY. Make sure fuel level is down in tank.
sometimes after fueling or just by turning on the car the check engine light would come on and it would say check gas cap so every time i would fuel i would tighten the gas cap extra hard and i would push and tighten and i never saw the check gas cap message ever again.
just bought this two days ago, gas cap message came up yesterday, light came on today for check engine and the gas cap light is still on. going to try to replace the gas cap and see if it fixes it