DTC P0731-00: Gear 1 Incorrect Ratio: General Description
WARNING: This page is about a different car, the 2024 Kia Sorento. However, it is still accessible from the selected car via links, so may be relevant.
Input speed sensor value must be equal output speed sensor value times each gear ratio at each gear position of transmission. That operation value equal with TCM operation value. For example output speed sensor value is 1000 RPM and 1st speed gear ratio is 4.400 then input speed sensor value must be 4400 RPM.