I had a new fuel pump installed in my 2017 1500 SLT 3.6L around the 170,000 mile mark. Shortly after that replacement, I started to get the the gas cap error message and idiot icon. I called the service guy back and he said that 1) this is a common issue with Ram trucks, and 2) it should not affect the running or performance of the truck. He told me to swing buy, and he cleared the error code. I then bought a new $25 gas cap, just in case. Around the same time I scanned this forum and read that many, many other Ram owners also experience this issue, and some have gone to great expense to have it "fixed" only to have the error code pop up its ugly head yet again. Ram is well aware of this issue, and they agree that it does not affect the running or performance of the truck, so it's a back-burner issue for them to attend to. The forum messages I read gave two temporary remedies. 1) Get yourself an error code reader that allows you to clear error codes, or 2) disconnect the (-) negative battery terminal for 30 seconds to clear the error code. I did the second option to great success. The only thing I need to do afterward is reset the time on the trucks clock. That gas cap error popped up again a few months later. A 10mm wrench and 5 minutes is all it takes. I have had to do this maybe three times over a 50,000 mile range. Don't let the dealer service con you into an expensive repair before you just reset the error code. It will likely pop up again, but not for quite a while, and if it does, reset it again.