Hi, Candy; I've run into quite a few different makes and models where the radio continues playing after turning off the engine until the door is opened. Just a guess. As far as the CEL illuminating, you'll need to have the trouble code pulled and we can go from there. Most part stores will do that for free.
The radio kept playing when we turned off the Jeep. We disabled the battery restarted and it was fine. Now this morning the check engine light is on. When I tried the remote start the dashboard had remote start was disabled. Any ideas?