Hyundai Repair: squeaking while driving, hyundai accent, engine performance

Question
This weekend while I was driving home from Michigan (a 380 mile drive) my service engine light came on, then about 200 miles later my car started squeaking while I was driving down the interstate. Now, I've made an appointment but I'm wondering what the problem might be.  I own a 204 Hyundai Accent with 103,000 miles.  
Tracy

Answer
There are a large number of things which can cause the check engine lamp to illuminate (too many for me to list), and I'm having trouble thinking of anything which would cause a squeaking noise and also cause the check engine lamp to illuminate while not causing an issue relating to engine performance.  It's quite possible you have two separate issues.

Ordinarily, I'd ask you to have the trouble codes retrieved so I could have some sort of idea of the nature of what was recorded by the engine control module relating to the problem, but since you've already made an appointment, this step is rather moot.  

Once the shop receives the car, their first steps will likely be a test drive and a check of the diagnostic trouble codes.  I expect they'll take the information on the nature of the problem causing the check engine lamp and then assess the likelihood this is also causing the squeaking noise.  

If you have suspicions that the shop is being dishonest or is not properly diagnosing the vehicle, follow up with me with as much information as you can.  Ask them for the numerical trouble codes that were stored as well as an explanation as to why each part of the repair is recommended.