DETROIT >> Kia Motors America is recalling nearly 73,000 Rio small cars to fix an air bag problem.

The National Highway Traffic Safety Administration says on its website that the recall affects cars from the 2006 to 2008 model years.

A sensor mat inside the front passenger seat can crack and fail to detect whether a child is sitting in the seat. This means the air bag could inflate in a crash and injure the child. Cars are designed so air bags don’t inflate if a child is in the front passenger seat.

Kia says in the documents that it doesn’t know of any injuries stemming from the problem.

The cars were built between Feb. 20, 2005 and Dec. 9, 2007.

Kia will replace the sensor for free starting in July.