Kia Optima: Auto door lock/unlock feature (if equipped)

Impact sensing door unlock system (if equipped)

All doors will automatically unlock when an impact causes the air bags to deploy. ...

Speed sensing door lock system (if equipped)

All doors will be automatically locked after the vehicle speed exceeds 15 km/h (9.3 mi/h). And all doors will be automatically unlocked when you turn the engine off or when you remove the ignition ...

See also:

Replacement
Standard values, such as torques and certain adjustments, must be strictly observed in the reassembly of all parts.If removed, the following parts should always be replaced with new ones. ...

Gasoline containing alcohol and methanol
Gasohol, a mixture of gasoline and ethanol (also known as grain alcohol), and gasoline or gasohol containing methanol (also known as wood alcohol) are being marketed along with or instead of leade ...

Suspension System. Tires/Wheels. Wheel. Repair procedures
Hub nut tightening sequence Tighten the hub nuts as follows. Tightening torque:88.3 ~ 107.9N.m (9.0 ~ 11.0kgf.m, 65.1 ~ 79.6lb-ft) ...