Intelligent Transportation Systems are being deployed all over the world, providing new applications and services that could prevent accidents, help regulate traffic and the automotive industry in designing energy efficient vehicles. However, enabling vehicles to communicate with the rest of the world ultimately leads to new security challenges with connected vehicles becoming new interesting targets for malicious actors. Thus, safeguards need to be deployed to detect malicious and anomalous activities in vehicular communications. This paper presents an approach to anomaly detection based on an ontological representation of cellular vehicular communication.