we will do for sure Do checkout our dem interview questions video : ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-EAbFvIeZMME.htmlsi=-mtnqbPFeGA8mFn_
yes you are right . 19 02 is to read Report DTC By Status Mask, but 19 04 Report DTC Snapshot Record by DTC Number , so you will get to know the DTC status byte for a individual DTC
As we have denouncing method to log the DTC .to clear DTC we have CDI. but DEM can clear DTC itself by 'Heal Denouncing method ' which can be counter based or time based. For example if the Application Swc saying there is no error to Dem then After aging (configured certain period) then dem clear the error itself ( please correct anyone if i said something wrong)