A maintenance services logging system is a useful tool for car owners to keep track of the car's condition and also can increase the market value of the car. Logging systems range from manual, paper-based, to automated, cloud-based systems. The automated process provides ease of use and availability of the records. A secure protocol is required to ensure that the workshop and service record are authentic, and hence the records are reliable. In this paper, we propose a secure protocol for automated maintenance services logging systems, through the use of a mobile application called AutoLOG. The multiple electronic control units (ECUs) used to support the connected and intelligent vehicle's technology are used to support the digital automated logging system. The car is the trusted entity that generates the log. The records are stored in an authorised mobile device and uploaded onto a cloud server to ensure availability. The proposed protocol is implemented to measure the performance and is formally analysed using Scyther and CasperFDR, with no known attack found.