I recently took a second-hand 2011 Land Cruiser for a test drive, and it would not disengage from low 4WD. When I told my mechanic about it, he was not surprised and said it was a common problem. Apparently the (electronic) low 4WD engage/disengage mechanism is located in a place where it is affected by water - even over-zealous spraying with a car-wash hose can cripple it.

Why would a manufacturer of off-road vehicles build them with such a vulnerability, and do you know which year Toyota changed from a manual selector to this electronic one?