One interesting incident I experienced was the appearance of the "gearbox fault" message every time I went round a sharp right hand curve. The problem eventually proved to be a loose connector in a part of the harness that connects to the electronically controlled transmission. I have since heard from several other owners with the "Gearbox Fault" message. It apparently indicates that voltage to the transmission selector mechanism is insufficient. Another cause is failure of the transfer box ECU to communicate with the BeCM due to a bad connection or connector.
Your battery is low, i had this message just recently. I have current leak somewhere and battery goes weak in 24h, it starts engine, but weaker than normal. Gearbox fault comes to screen, but it goes away after driving good trip.