With chip tuning Citroen XM - will improve the performance of the car will increase the power of the engine and its torque. In addition, working efficiently drive unit enables fuel economy while maintaining a similar driving style. Chip tuning Citroen XM can be done in two ways, through the diagnostic connector OBD2 or after removing the computer control - ECU. Increasing the power Citroen XM is done by reprogramming the original map of the engine, so there are no hazards associated with compatibility and unstable operation, as is the case with ready-made programs of unknown origin. Citroen XM vehicle is prone to chip tuning, and the results of our work, we confirm the chart of professional chassis dynamometer stress 4x4 brands Dyno Project. The results of research vehicles before and after modification to increase the power, really show the benefits of chiptuning.