2004 Hyundai Elantra vehicles manufactured between June 12, 2003, August 11, 2003. If the front passenger seat is unoccupied or is occupied by someone lighter that 56.4 pounds, the passenger airbag is deactivated and will not deploy if an accident occurs. However, the occupant classification sensor may incorrectly interpret that a seated adult is an infant seat and deactivate the passenger airbag if someone heavier than 56.4 pounds who is seated with one leg resting on the outboard or inboard edge of the seat; with legs spread; or positioned off-center toward the center console and with his or her arm leaning on the console.

In the event of a vehicle crash, the airbag may not deploy, possibly resulting in serious injury to the right front passenger.

All affected vehicles were delivered to Enterprise Rent-A-Car and will not be placed in service until the recall repair work is complete. Customer notification for this campaign is not necessary.

Certain vehicles equipped with an Occupant Classification System (OCS) fail to comply with the requirements of Federal Motor Vehicle Safety Standard No. 208. "Occupant Crash Protection." the OCS installed in the right front seat of the vehicle may misclassify a Child Restraint Seat (CRS) as an adult. This may occur if the CRS is installed after an adult has been seated in the right front seat. If there has not been a 'key on' ' key off' cycle with the right front passenger seat empty prior to installation of the CRS.

The possibility of misclassification of a CRS as an adult may allow the right front airbag or side impact airbag to deploy in a crash and could result in injury to the right front occupant.

Dealers will reprogram the vehicle's OCS electronic control unit (ECU) to remove the feature that may cause the CRS to be recognized as an adult. The recall is expected to begin during October 2005. Owners should contact Hyundai at 1-800-633-5151.