Emissions failure OBDII DTC P0430

My truck is the extended cab model.
Runs normal.
Need emission inspection for new tags. Failed
Catalytic Converter - Pass
PO430 - Catalytic Converter System Efficiency Below Threshold (Bank 2)

December 2016 102,664 miles - synthetic oil, oil filter, lube, replaced alt belt and serpentine belt, checked air filter (last replaced at 99,500)

Ran 25 gal tank with fuel system cleaner on 15, 00 miles freeway trip and towed a vehicle on return leg. Service Engine Soon Light was on solid.

Disconnected battery negative cable. Reconnected three hours later. Service engine light came on immediately.