Error detection and error recovery mechanism must be carefully selected in automotive embedded applications mainly because of limited resources and economical reasons. However, major safety concerns, brought by new customer services (i.e. chassis control), motivate the automotive industry to search for new means for improving robustness in operation. The challenge is to study a "low-cost", portable and flexible dependability solution. The guiding principle is to rigorously control what/when information is essential to get, and what/when instrumentation is necessary, to perform fault-tolerance. The paper proposes an approach to develop a defense software, as an external customizable component, based on observation and control mechanisms provided by current standard in the automotive industry.