The Selective Catalytic Reduction (SCR) system, installed on the exhaust line, is currently widely used on Diesel heavy-duty trucks and it is considered a promising technique for Euro 6 compliancy for light and medium duty trucks and bigger passenger cars. Moreover, new more stringent emission regulations and homologation cycles are being proposed for Euro 6c stage and they are scheduled to be applied by the end of 2017.In this context, the interest for SCR technology and its application on light-duty trucks is growing, with a special focus on its potential benefit in term of fuel consumption reduction, thanks to combustion optimization. Nevertheless, the need to warm up the exhaust gas line, to meet the required NOx conversion efficiency, remains an issue for such kind of applications.In this work, the activity performed on different Euro 5-compliant light-duty vehicles, equipped with SCR, to fulfill Euro 6 emission level with fuel saving respect to current production level, is described.An initial experimental investigation on test bench has been carried out to identify the effect of the main control parameters, in order to achieve the required NOx emission reduction with the best fuel economy performance. After this preliminary identification phase, different calibration strategies have been assessed executing several NEDC cycles. The most relevant achieved results are illustrated and critically discussed in the paper.