ISO 26262 is an international standard about functional safety published on 2011, aiming to avoid failure in safety related electrical and electronic systems in passenger cars. A corresponding standard for heavy vehicles is expected to be published in a few years’ time. In order to be well-prepared, the heavy vehicle manufacturer Scania decides to start investigating what impact ISO26262 can bring. At Scania, modularization is one of the most important features of the product, which means several modules can be combined together into a vehicle in a variety of ways, so that highly configurable products can be provided for the customer. Huge number of unique module combinations bring big challenges to systems integration testing department REST/I in Scania because of limited time and resource availability for testing. Nowadays, people in REST/I deal with the variant mainly based on human experience, which is quite difficult to obtain the exact complete variant information and concrete testing coverage. In order to fulfill the requirement related with variant handling in ISO26262, better variant handling methods are proposed in this thesis, which can mainly be divided into two parts: method for variant generating and method for configuration selecting. To simplify the implementation work of this thesis, only the ECU components are focused on (other components such as sensors are ignored), and the risk-based feature is not added to the configuration selecting. Variant generating is to generate variant information from Allocation Element Diagram in Sesamm database systematically. According to the generated variant information, the configuration can be selected automatically by using Greedy best-first-search algorithm based on the proposed testing coverage metrics. Since all these work can be done automatically by computer, REST/I not only can work more efficiently by saving a lot of labor resource, but also can avoid mistakes caused by anthropogenic factors. However, not all the data needed for the automation are existed today, so the suggestions for consummation of the data to be ready for implementing the proposed methods are also mentioned in this thesis.