product function: the cr injector tester is applied for cr system repair in three aspects: (1) to test if the cr injector is still function to connect a cr injector to a high pressure fuel source by a high pressure fuel line,and to the cr tester by harness. the tester is set to continuous injection mode. the cr injector is in normal condition, if it is capable to inject fuel under the driving signals by the tester. (2) to test injector spray atomization,to connect a cr injector to a high pressure fuel source by a high pressure fuel line and to the cr tester by harness. the tester is set to single injection mode to allow observing the nozzle spray pattern to judge if the nozzle is normal or orifice plugged. (3) checking the injectors return oil and injection oil. design features 1.modulated driving signal to ensure the safety of the solenoid of the cr injector 2.the frequency and the pulse width of the driving signal are user adjustable. 3.short circuit protection for the output circuitry of the solenoid driving signal