• Clear DTCs: Tap to clear the existing diagnostic trouble codes. 1.2.2.2 System Scan (Automatic System Detection) This function will scan the vehicle test system automatically. Tap “System Scan." The following screen will appear: 1.2.2.3 System Selection (Manual System Detection) This function allows you to manually select the system and perform the related diagnostic functions. Tap “System Selection." Select the desired system (take “Engine” for example), the following screen will appear: 15