Are you saying that ONLY when you have the Manual button switched in/on the gears can be selected properly with the selector lever, including first (1)? Please confirm or explain in detail.
At this stage it would appear that all is OK when not under electronic control and accepting this as fact the following comment applies:-
I do not have data on the US model and there are two speed sensors, one of which is the primary sensor and I would suspect this to be numbered as No. 1. From what you report, you could very well have an intermittent speed sensor which is not registering a constant fault signal. On this basis I would replace speed sensor No. 1 as a first option.
