Hi Jagesh,
I faced the same issue 1 week back.
We did the following:
1) Program Id registration on PI server.
2) Implementation of SAP note#0001850230 as mentioned by Mark
2) Basis team also did some configuraton changes as per note#1592493
3) Made sure RFC Destination in ECC is pointing to ECC gateway host and service and not PI.
Hence the issue was resolved.
Regards,
Pooja