Short Term FT Bank 1

Display shows counts from 0 to 255 and percentage from -100% to 99%. The normal position for the short term fuel trim is 128 counts or 0%. A count greater than 128 or a percentage greater than 0% indicates that time is being added to the injector pulse width, increasing the amount of fuel to the engine to compensate for a lean condition sensed by the bank 1 (rear) HO2S. A count less than 128 or less than 0% indicates time is being subtracted from the injector pulse width reducing the amount of fuel to the engine to compensate for a rich condition sensed at the bank 1 (rear) HO2S.