Common Rail System Tester simulates an engine ECU to drive a pump solenoid, such as Bosch CP1/CP2/CP3, Delphi CRSP and Denso HP2/HP3/U2, plus solenoids of six CR injectors. A standard high pressure pump test bench with a CR system tester CRS will fulfill most tasks for repairing a CR system and the components, such as injection quantities, injector fuel return, nozzle injection spray atomization, pump condition and fuel rail pressure control.