AIR Fuel Ratio

The scan tool range is 0.0 to 25.5. Air Fuel Ratio indicates the PCM commanded value. In closed loop, the air fuel ratio should normally be around 14.2 - 14.7. A lower air fuel ratio indicates a richer commanded mixture, which may be seen during Power Enrichment or TWC Protection modes. A higher air fuel ratio indicates a leaner commanded mixture. This may be seen during Decel Fuel Mode.