Gas cap off on 2006 chevy Colorado and check engine light came on. Replaced cap now how do I get check engine light off.

Have you monitored the engine sensors when this happens, if not have that done.

put gas line antifreeze.

Trouble Code: P0171

Fuel Trim Too Lean

Possible Causes:


The current cell can be observed using a scan tool.The system will go lean if an injector is not providing enough fuel.A lean condition could be present during high fuel demand due to a fuel pump not pumping enough fuel, plugged fuel filter or a restricted fuel line.Insufficient fuel in the tank or low fuel pressure may cause this DTC to set. Refer to Fuel System Diagnosis .Review the Failure Records with a scan tool. If an intermittent condition is suspected, refer to Intermittent Conditions .

If all it was is that you did have it off it will reset by the 3rd drive cycle. It may take between 50 & 200 miles.

http://coloradofans.com/forums/viewtopic.php?f=8&t=52458

To many things that can cause the check engine light to come on. It could be as simple as a bad gas cap to a miss fire in your ignition system.
If there is an Auto Zone around your area, they scan for the DTC codes free of charge and when the issue has been addressed. The check engine light will reset if self after 3 consecutive start cycle if there is no oter issues.
Thank you for using fixya and good luck

Turn key on (do NOT start the engine) now depress the gas pedal, to the floor 3 times, now turn the key off. now start the car, the light should be off, if not, try it again.

there is a large evaporative leak. keep away form ottozoo, they dont have the brain power to actually diagnose a light bulb., their job is to sell parts., if they sell you the wrong parts tough.Take it to a qualified repair shop that does a lot of GM work or the dealer.

you have several hundred codes it can be, your guess is as good as anyones

You will need to remove the Cap with Pliers. It has a Vapor Lock on it and you May need to Replace the Cap Also. Please Rate My Response! Thanks!