# The principle of active and passive events
> | In vehicle diagnosis, a distinction is made whether an event is currently active or passive. The "active or passive" condition also influences how events are processed, e.g., when being deleted. Active events are events that are found in the vehicle at the moment when the event memory is read. Passive events are events that were active but the fault has already disappeared and is thus no longer found in the vehicle at the moment when the event memory is read. If an event changes its state from passive to active, i.e. becomes active again, this will be counted in the event memory and displayed in the ECU report in the line "Frequency of Occurrence". The frequency counter counts up to the value 250. If an event occurs more often than 250 times, the counter value for the frequency is frozen at the value 251. Example: If a cable break occurs, this fault will be entered as an active event in the event memory. If an upload should be performed now, the fault will be displayed as an active event in the report (fault can be found in this form in the vehicle). Should the fault disappear, e.g., a loose contact in the cable, so that the cable is conductive again, the status in the event memory will be changed from active to passive. If an upload is performed now, the fault will be displayed as a passive event in the report. After a certain time, the loose contact is no longer conductive and the fault becomes active again. An additional entry in the event memory states that the fault occurred for the second time. If an upload should be performed now, the fault will be displayed as an active event and the frequency of occurrence is '2'.
> Symbol | Meaning
> | Active event
> | Passive event
| Further topics:
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