Just picked up my 2018 Sonata 2.4l from the dealership, new harness installed. It was the harness that put my car into limp mode. Wiring harness I guess from factory is short and taunt, routed too close to body/ frame causing it to pick up a different frequency throwing ECM into protection mode. New harness is longer and rerouted away from body and frame. Works like a charm now. Thanks for all your information you gave me in helping with the situation.