The SUV is running fine but engine light says C0055?

Question

How do I know it's a rear wheel speed sensor

Answer 1

C0055 Rear wheel speed sensor circuit

Thats correct because usually when this code occurs it the EBCM (Electronic brake control module) This is for the ABS system that your vehicle has, The way to find the problem is to measure the voltage between the vehicle speed sensor and ground.This would determine what direction this diagnosis would go.