One problem related to battery dead has been reported for the 2003 Hyundai Sonata. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2003 Hyundai Sonata based on all problems reported for the 2003 Sonata.
Purchased 2003 Hyundai Sonata brand new. Defective radio replaced 1 month after purchase. Battery dead after 2 years and 8,500 miles. No reason. Battery replaced by myself. Battery dead again in August of 2006. Replaced again. Battery dead again on December 30th 2006. Had to have car towed to dealership. Dealership stated the battery was bad. Replaced again at my expense. I said the car should not be draining 3 batteries with less than 10,00 miles. Dealership said it was because of a defective radio!?! and that I needed to replace the radio at my expense because the radio ran out of warranty 5 months prior! I believed that there was something electrical wrong with the car and I do not think I can trust the vehicle now.