The check engine light came on less than two weeks after the car came from the dealer service department for an emissions fault, which caused the car to stall and idle up and down unannounced. The service department rep told me that he did not do anything but run a diagnostic and that cleared the fault. The check engine light that's on now is an air pressure fault that the service department cannot detect or fix.

When the Check engine light comes on it is indicating a fault in the systems of the engine has been detected or a problem in the emission control system. When that light is on a fault code is set, you need to have the fault code read, then based on the code you do the diagnostics outlined in the factory service manual. Any Autozone or O'reilly auto parts will read the codes for free except in the state of Calif.

could be a engine /transmission fault recorded or a reminder that the vehicle is due for a service
take it to an accredited service dealer and have the fault code read, repaired or serviced and the light reset.

Take it to autozone or another place like it and have them read the codes and tell us what they are.

The information below was complied by me, it explains what causes the check engine light to come on and the process of finding the cause.
When the Check Engine light (or Service Engine Soon) is turned on, the systems computer control unit (called the PCM) has sensed a fault in the electronic controls of the engine and/or the emission system. When this happens you will seldom feel the car engine run any different. There are about 200 possible system faults (the gas cap is just one of them) that turn the Check Engine light on, to know what has developed a problem you must have the system tested, this is called an OBD2 fault code test, Kragen/Oriley and Autozone parts stores (USA only) do this testing for free.

This is the emissions system warning light, commonly referred to as the "Check Engine" light.
Please read on.

The information below was complied by me, it explains what causes the check engine light to come on and the process of finding the cause.

When the Check Engine light (or Service Engine Soon) is turned on, the systems computer control unit (called the ECM) has sensed a fault in the electronic controls of the engine and/or the emission system. When this happens you will seldom feel the car engine run any different. There are about 50 possible system faults. To find out which one is causing a problem have the system scanned by a local shop with a MB compatible scan tool.

you have a sensor on the engine setting a trouble code. need to have the fault code pulled to see what is malfunctioning.

You only need worry about the CEL (Check Engine Lamp) if you live in an area that has Enhanced Emissions Testing (like California).
I would guess that the code that caused your CEL to come on refers to a leak in the Evaporative Emissions System (EVAP).
At the age of your vehicle and it's mileage, it is indeed covered under both the basic and Emissions warranties. Be aware that it is standard dealer procedure to require your authorization for inspection and diagnosis of the problem. Usually 1 hour of labor. If the service department determines that the problem is covered by your warranty, then you should be no charged.

Did you replace the gas cap? Also check the filler tube that's where the gas cap snaps on where you put gas in. The filler tube or neck has a thin lining of plastic at the top look for small cracks in it where the gas cap goes on. It there's cracks in it, it will cause an emission leak and sometimes a dealer won't find it until you spent a lot of money on diagnostics. And it depends if there best mechanic was working on it.

Not the fuel filter, this is an emissions problem. Sounds like it is in Limp Mode. You need to have the ECU scanned for trouble codes. Is this vehicle not still under warranty for the emissions system? Call your Dodge dealer and find out.

The SERVICE light coming on, indicates a fault detected by the vehicles on board computer. The fault might be transmission related, or possibly engine/emission related. Push the OFF and WARM buttons TOGETHER on the climate control panel ( with the ignition key on ) Hold for 5 seconds and failure codes should appear . Relay your findings. Hope this helps