Did the turn key code check and got P0456. Gas cap might have been loose.. That it? Tighten it and drive for a while and the light should go off? When do I take her to the Dr? Jan 10, 2015 · So got my first CEL since i bought it 2 1/2 Years ago. P0456. After reading its referring to a small leak in the Evaporation System. First everyone This page last updated: September 19, 2010. Jeep Commander Technical Service Bulletins. 2006-2010 model years Jun 06, 2018 · Last night while derving my 2010 JK sport the "gascap" message popped up. 10 mins later the check engine light came on. I checked the DTC’s once I got home and I had a P0455, P0456, and a P0457.