Down pool member at f5 standby

has it ever worked? monitoring is sourced from a BIGIP's non-floating self IP address, are there any ACLs, firewalls etc. which may be blocking access from the standby one to the pool member? Have you run a packet capture, like tcpdump, on the standby to see what may be going on? Are you monitoring the node with ICMP and is this up/down?