The contact owns a 2019 Kia Optima. The contact stated while starting and driving at an undisclosed speed, the ‘Check Blind Spot Collision Warning System’ and ‘Check Forward Collision Avoidance Assist System’ messages became displayed. The ABS, traction control, and several other unknown warning lights were illuminated. The vehicle was taken to the dealer, who retrieved DTC codes: C121002 and C121102. The dealer replaced the rear wheel speed sensor. The manufacturer was not made aware of the failure. The failure mileage was approximately 20,000.