Questions about A/F Ratio not reading on KPRO

Does anyone know why my A/F Ratio is not reading on KPRO ? I have a check engine light code for "P1166". I know it's a code for the primary but wouldn't it still read A/F Ratio ? I was assuming this would apply for the Secondary o2.
Any help would be appreciated.

Questions about A/F Ratio not reading on KPRO