Service aid for SCR (Selective Catalytic Reduction) post-processing system

The invention provides a service aid for an SCR (Selective Catalytic Reduction) post-processing system. The service aid comprises a DCU (Dosing Control Unit) linking module, a data monitoring module, a fault code information module, a diagnosis testing module, a characteristic parameter setting module and a calibration module, wherein the DCU linking module is used for linking the service aid and a DCU of the SCR post-processing system; the data monitoring module is used for reading and monitoring operating data of an engine and operating data of the SCR post-processing system and playing a role in troubleshooting fundamental faults through monitoring feedback of the operating data of the engine and the operating data of the SCR post-processing system; a fault list is created in the fault code information module and contains various codes and corresponding fault meanings; the fault code information module is used for reading fault codes from the DCU of the SCR post-processing system and finding out fault mean