This research paper presents a blockchain-based approach for fault detection and secure communication in vehicular ad hoc networks (VANETs). VANETs are an emerging technology that allows vehicles to communicate with each other and with the surrounding infrastructure to improve safety and efficiency on the roads. However, the decentralized and dynamic nature of VANETs makes them vulnerable to various types of attacks, including false data injection and communication interference. To address these challenges, the proposed approach utilizes blockchain technology to ensure the integrity and authenticity of data exchanged among vehicles and the infrastructure. The system also includes a fault detection mechanism that can detect and isolate faulty vehicles to prevent them from disrupting the communication network. However, VANETs are distinct from conventional mobile ad hoc networks due to the high mobility of vehicles, which creates dynamic network environments and frequent link interruptions that result in message loss. A hierarchical defect detection method based on dead reckoning is proposed to address these issues. The technique uses the dead reckoning model to predict the transmission time of pulse messages and builds a hierarchical detection architecture with Roadside Units (RSUs) functioning as static nodes. This architecture enhances the efficacy of VANET fault detection. The proposed method was validated by NS-2 simulations, demonstrating superior performance in terms of detection speed, accuracy, and detection burden compared to the baseline fault detection method.