Dealership charged $125 for the diagnostics and told me it (DTC P1456) was due to a loose gas cap and reset it. After 3 weeks, it comes on again. Dealership told me it is the same problem and blamed on loose gas cap. Both time the gas cap was tightened. I am very frustrated right now. Any suggestion to deal with this problem?

 

new gas cap? Maybe it is not letting the fuel system build pressure. Just me .02

 

Pay them to fix it, if it happens again, take it back to them and let them deal with it.