Long Term Ft Bank 1 and Bank 2

The scan tool displays Percentage. The PCM derives the Long Term Fuel Trim from the Short Term Fuel Trim value. The Long Term Fuel Trim represents a long-term correction of fuel delivery. A value of 0% indicates that fuel delivery requires no compensation in order to maintain the PCM commanded air/fuel ratio. A negative value significantly below 0% indicates that the fuel system is rich and the PCM is reducing the fuel delivery (decreased injector pulse width). A positive value significantly greater than 0% indicates that a lean condition exists and the PCM compensates by adding fuel (increased injector pulse width). Fuel trim values at maximum authority indicates an excessively rich or lean system.