p0449 error code

Hello
I want to start with the gas cap, 7 bucks at autozone,,,, but if that does not work, if someone would please point me in the right direction I would be most greatful.

Welcome to AF!!

This code indicates that the solenoid that controls the evaporative emissions system is malfunctioning. You will need to replace it with another one. Also check the vacuum lines to the solenoid as they may be damaged as that can cause the same problem.

I am not sure where it is located on the Montana but it should not be hard to find. Once it has been changed clear the code and see what happens.

Could be the valve (solenoid), or the wiring to it. Could be an open or short. I believe there is a connector right below the driver's seat (under the van). I believe the actual valve is near the gas tank.

Randy didn't mention what year the van is, but my manual says for a 2001 model:
"The PCM detects that the commanded state of the driver & the actual state of the control circuit do not match." and
"The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test ran and failed."

Also: "The PCM will turn OFF the MIL during the third consecutive trip in which the diagnostic ran and passed." Or you could clear the code with a scanner.

Hope this helps.

Take Care,