One problem related to battery has been reported for the 2004 Hyundai Sonata. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2004 Hyundai Sonata based on all problems reported for the 2004 Sonata.
Battery, the battery was replace in 12/05/05, then again in 10/05/06, on 7/31/08 the battery this time die with no warning, in the middle of the very busy intersection. Both time the battery was replace by rick case Hyundai, stated bad battery.