Primary vs Secondary O2 Settings & Fuel Trim Behavior
Posted: Sat Nov 07, 2026 12:20 am
Regarding the Primary and Secondary Oxygen sensor settings:
As I understand it, the Primary O2 sensor controls AFM-based closed-loop feedback and fuel trims (S.Trim / L.Trim).
However, in my testing:
- When I disable the Secondary O2 sensor, [AFM and : S.Trim and L.Trim stop updating / remain inactive].
- When I disable the Primary O2 sensor, [AFM and S.Trim / L.Trim keep updating / remain active].
Am I missing something in how Hondata handles these sensor parameters?
As I understand it, the Primary O2 sensor controls AFM-based closed-loop feedback and fuel trims (S.Trim / L.Trim).
However, in my testing:
- When I disable the Secondary O2 sensor, [AFM and : S.Trim and L.Trim stop updating / remain inactive].
- When I disable the Primary O2 sensor, [AFM and S.Trim / L.Trim keep updating / remain active].
Am I missing something in how Hondata handles these sensor parameters?