When someone new comes along with a code, what I usually do to help them is to do a google search. Type in "Chrysler fault code P1494" to see what others have done with the same code.
Here's some I found......
"P1494 (M) Leak Detection Pump Sw or Mechanical Incorrect input state detected for the Leak Detection Fault Pump (LDP) pressure switch" is the actual 1494 error code.
The code could be set for a number of reasons such as a faulty gas cap, cracked vacuum lines, solenoids & vent valves stuck to the pump itself. It can be a very difficult fault to cure being it doesn’t take a very big leak anywhere in the system to set the code and that’s if it’s a leak and not an electrical or mechanical fault.
Start with the easiest, look at your fuel cap. Is the gasket good? Buy a new one, clean where it seats well, put it on making sure it clicks at least 3 times, and see if that solves it. If not you will have to start looking at hoses for hairline cracks. And yes, although it's rare, sometimes the canister itself gets a crack and needs to be replaced. It will be a dealer only item of course.
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check the gas cap for signs of rust
check hoses by the purge solenoid.and by the throttlebody on the intake manifold and replace if cracked
per Chrysler/jeep training
a code must not be erased ,rather fix the problem and let the car run 3 good trips.you accomplish this by running vehicle like you normally do(if you do not have a (drb3)(scanner)until the car no longer "sees" the problem on three consecutive self diagnostic tests.the car will then clear the code meaning the problem is solved
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On a personal note. My wife's brand new KIA had the engine light come on a full day after I filled it up. There's no way to get the code on a KIA without a scanner. Car was running OK and I called the dealer for an appointment. They said "check the gas cap", and I said SURE, the old gas cap trick. But I did take it off and put it back on making it click shut at least 4 or 5 clicks, and made the appointment anyway. Before the appointment came around, the light went out.
I guess it really was the gas cap. Sounds like you might have the same thing.