Operation for performing diagnostics, such as vehicle diagnostics including short circuit and low impedance diagnostics during a high-voltage (HV) battery pre-charging a power-net of the vehicle and including insulation resistance monitoring diagnostics for measuring an insulation resistance between the power-net and another power-net, with reduced processing time includes measuring a physical parameter (voltage or current signal) as the parameter is being generated by a device-under-test to which the diagnostic process pertains. The diagnostic process requires a stable value of the parameter. The parameter variates while being generated during a beginning time and is stable while being generated during an ending time. While the parameter is being generated during the beginning time, a stable value of the parameter which the parameter will have during the ending time is predicted. The stable value of the parameter is predicted based on variation of measured values of the parameter during the beginning time.