Method for testing the operation of a system for post-treatment of exhaust gases from an engine and vehicle suitable for implementing the method

The method involves estimating balance pressure at the level of a pressure sensor (20) based on external temperature, where the sensor is placed between a reagent tank (16) and a dosing unit (18) i.e. electrovalve, that injects reagent in exhaust gas in open position of an exhaust gas post-treatment system (10) i.e. selective catalytic reduction (SCR) system, of a vehicle. Pressure measured by the sensor is compared with the estimated balance pressure and with external pressure. An independent claim is also included for a vehicle comprising an exhaust gas post-treatment system.