Hi,
I had that. My CVT is fine but its speed sensor needed replacing (p1720). Call Sensor Pro Limited Hutchinsons Road, Bucklands Beach, Auckland. Tell them the error code and buy a replacement. Go pick up the part and ask them to show you the part's location on partsouq.com. (it's near the starter motor on top of CVT, under throttle body...). Quick and easy. Part was $80 cost I think). Fixing the error p1720 tells the part reporting p1715 errors that all is well so both can be cleared from fault log. I hope.