Remote starter quit working '09 Impala

Wife reported that she started the car with remote, not more than 2 minutes later the car had shut off. She restarted the car manually and drove home. She then told me a light in the dash ( check engine light ) came on and stayed on. She said nothing else seemed wrong as she drove home. No noises. Any and all help is appreciated.

Any time the CE light comes on, this disables the remote start.....

So the first thing to do, is get the code read....AutoZone will read it for free.....

After taking it to AutoZone ( thanks for the tip! ) it turned out to be a vent valve.
The trouble shooting says probable cause:
1. Purge or vent solenoids defective
2. Check connector and wiring
3. Fuel saturated vapor canister
4. Failed EVAP vent solenoid

The guy at auto zone also mentioned that the rain and then very cold weather in our area in the past couple of days may have caused this part to malfunction and said to give it a few days to see if it would fix itself then reset. It is only a 56 dollar part but have no where to work on it now that it is so cold. He told me the only problem ( besides the non working remote starter ) would be a bad emission test but here in Wisconsin I have never seen/heard had one done in 40 years.

When I DO want to replace this is there a step by step anywhere? Thanks so much!

You did not list the code......

Remember, a huge diagnostic problem made by a lot of techs, is just replacing the part the code is named after......unfortunately it takes tools to diagnose this......what if you had no power to the solenoid? What if the ground was bad? What if a wire is open? what if there is a break in a vac line? More often than not, it is the vent solenoid, and proper testing would pinpoint this....

One thing you could have tried, with the code cleared by Autozone, try your remote to see if the car started.....it should start before that code is reset....

Code was P0449.

They also printed this out:
Definition
EVAP (evaporative emission system) purge/vent solenoid circuit condition.
Explanation
The solenoids and system wiring are monitored for opens or shorts.

Then it goes on with the probable causes.

Well, you can take a chance and replace the vent solenoid......usually located in the left rear quarter near the gas fill tube......

A GM shop would first command the system sealed...it does this by closing both the purge and vent solenoids with a scan tool.....and then with a smoke machine attached and running, you look for smoke coming from the vent solenoid....if there is smoke, you disconnect the harness to the solenoid, and attach a test light.....if it lights, you know the vent solenoid is commanded closed, and you have a bad solenoid.....if it doesn't light, then you have a problem in that two wire circuit......