I have a prototype of CCS2 controller (EVCC) up and running. I'm in the process of compatibility testing of my V2G stack with real DC charger installed in my area. The test set up is fairly simple my EVCC box only connect with CP and PE line and leave PP and High volt DC pin unconnected.
So far I manage to successfully initiate a dummy charging session with ABB Terra (50kw and 120kw) and Efaces charger, everything work fine form SLAC till session termination. Attached is the pcap file for ABB session
However with IES Keywatt60x, the session failed at CableCheck state, with a negative response code of FAILED_SequenceError, see a snippet of V2G message below
CableCheckReq:

CableCheckRes:

EDIT:
I add the design guide showing how thing should look like at this stage, my CP line has 5.7v in state C which should be in tolerance range and please note that the DC pin is left open during my test.

Does anyone has any idea of where should I look for clue to troubleshoot this?