Great, thanks! I'll check out those links.True, but not all OBD II readers have the ability to clear higher level DTCs. Obviously, if it is a failure, you can't clear it. The cheap units you can buy at Pep Boys can't clear much and if your vehicle uses CANBUS then you'll need a vehicle specific unit. I don;t believe the Jeep uses CANBUS.
So, it's possible that it just doesn't have the software to clear those codes.
Here's a higher level reader you could use, but I would save the Superchips unit as a tuner only device IMHO.
I have the i906 and its a great unit. It's Volvo specific and it's saved me hundreds of diagnostic dealer fees.
The i810 will work with Chrysler products.