CEL On, Car Is Loud
 

2004 Sebring Platinum Series V6
Around 75k miles

This is my parents' car. Mom has been driving it even though something was not right. I noticed when walking up to the car, that it's very loud. I can't tell if it's the engine or something with the exhaust, but I suspect it's the engine. Mom says the car isn't driving any differently. For a while, it was just louder than usual, but recently the CEL came on. I know this could be many things, but just trying to get an idea of what to expect when it gets serviced on Thursday. Any ideas?

Edit: Forgot to say the car hasn't been to Autozone or anywhere to pull a code yet.

You may be able to pull the codes by turning the key on-off-on-off-on without starting the engine and then read the codes in the odometer. There's not much we can tell you without the codes. If the "louder" sound seems like a hole in the exhaust, that could certainly cause a code to set (either an O2 sensor code or a catalyst efficiency code). If you can't lift the car to look at the exhaust system, you could try looking under the car when you start it on a cold morning and see if there's exhaust smoke coming from the wrong place.

Thanks! I will take a look.

An exhaust leak, especially one in the EGR system, can cause noise and will undoubtedly set off the exhaust back pressure sensor. (Included as part of the EGR valve.)