Excess oxygen in the exhaust stream sets a P0171 (bank 1 lean) or a P0174 (bank 2 lean) code. Although bank 1 and bank 2 generally refer to V-block cylinder configurations with an oxygen sensor on each bank, some in-line engines split their exhaust manifolds to create a B1 and B2, each equipped with its own oxygen sensor.
Grab your scan tool and meet us in the garage to learn more.
For our video on interpreting fuel trims, click HERE.
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