passing a smog check

This is why you always use a saver tool before you disconnect main power, so now you need to disconnect a battery cable, turn on he headlight switch, turn off the headlight switch reconnect the battery cable then start and drive a minimum of twenty minutes before checking again. Do not shut it off before that time has elapsed or you will need to do it all over again. This is a called drive time protocol.

There's a smog test ( tailpipe sniffer ) and ECC (computer ) emissions test . If you clear everything the inspector doesn't know if there was a trouble code with the emissions , so you have to drive it till the monitors are clear and there are no codes present , think of it as a computer scan , A scan tool has the feature to check monitors monitor feature . Once the monitors are O.K. and there are no codes up you can get your inspections . States can have different rules .Here in the vampire state you're allowed one monitor up and pending codes are O.K. I found all this confusing at first

Make sure the gas gauge is between one quarter and three quarters when you do the drive cycle. Some readiness monitors will not set if the gas gauge is not within those parameters. Normal driving for a day or two should reset the readiness monitors. Jim

If you drive for 2 days and no check engine light comes on then you're good to go , I would think