you create a site to stie vpn on ASA which is deploy as Active passive. from the active firewall you can reach the remote site. correct?
in order to reach the remote site from the passive firewall you have to failover and make the primary as standby and secondary as active than you in position to test it.
normally in active passive asa deployment the active firewall keep the session and keep syn the passive unit in case when the active fail the passive become active and inherit the connections. normally the transition from active to passive have a one ping loss.
please do not forget to rate.