on 2004-2006 x5 vehicles, especailly 3.0i varients, a faulty servo actuator motor for the transfer case causes the 4x4 and dsc lamps to illuminate. Additionally, a terminal 15 fault in the instrument cluster can cause the lamp to illuminate, this situation occurs when the ignition switch fails. the terminal 15 fault occurs when a kl50 signal is recognized, but the terminal 15 signal is missing.

if your mechanic has a GT1 or displus, communication with the VTG should be present verify that his equipment is up to par prior to parts replacement.