The cargo transportation in Brazil is predominantly done by road, instead of any other means of transportation. It represented more than 35% of the total amount of money spent on goods transportation on that South American country during 2005. Several factors should be taken in consideration in the final cost of this service. We can highlight, for example: poor road quality, cargo robbery, theft of tires, fuel stealing, road accidents, etc. These costs are always reassigned to the final customers. Among that list, one of main factors for increasing transport costs in Brazil is the illicit fuel deviation. In order to reduce this problem, entrepreneurs have adopted several strategies; so far, none of them could come up with an efficient proposal. This paper presents a new tool to assist preventing the fuel stealing issue. It can detect the tank violation, notifying the company when it happened and how much fuel was diverted. The proposed system is also capable of fuel tank level monitoring as a function of time, storing data and preparing it for post analysis as well. The system goes beyond a theft detection and alarm system; it also provides the telemetry of fuel consumption at each trip moment. This tool can help in reducing costs, not only in cargo carriage business, but also in passengers transport business.