A vehicular secure gateway system for a vehicle includes a central security gateway disposed at the vehicle. The vehicular secure gateway system includes a connected gateway and a secure gateway. The connected gateway receives wireless communications emanating from external of the vehicle. The vehicular secure gateway system is operable to enable a particular security measure based on determination of a need for that particular security measure. The particular security measure provides enhanced isolation of an on-board diagnostic interface at the secure gateway and enhanced protection of a data communication network of the vehicle. Wireless communications received at the connected gateway are routed through the secure gateway for communication, via a data communication network of the vehicle, to a driving assist system of the vehicle.