This is for Next Gen Equip. Only , the information was made avalible in the HUB DOC-152924, by Ray Russek info below is through Trane branded VRF Tech Support :
VRF GEN2 AUTO PORT PAIRING
Tech Service has seen cases where the APP feature will kick out after ODU power up.
What to be aware of when using the APP, K2 13 times feature.
If the outdoor unit is powered for anytime less than the IOM prescribed time, the unit will not APP.
Resolution
What we have seen is the unit has an internal timer that must expire before the logic with execute.
We have noted several cases where this feature has been unsuccessful at initial startup, but completed
the following morning.
We have completed a case study with a Trane technician who was able to get
one system to APP, but the other unit would kick out. We instructed him to leave the unit on for a
minimum of 6 hours and the unit successfully executed the subroutine.
Please be sure to complete any missing information on your component location sheets
As this information may be referenced for discrepancies and our product warranty requests.