"System too lean, bank 2" is the same reading as P0171 on the engine's other cylinder group: the fuel correction on bank 2 reached the end of its range in the direction that adds fuel. Only engines with two banks can report it. Which cylinders are bank 2 is the engine computer's own numbering, not a physical side of the engine bay.
This is a standard code. It means the same thing on every make of vehicle.
Short fuel trim and Long fuel trim are the readings this code is about, and the Full scan's on-board self-tests list the oxygen sensor results by bank and by sensor, which is where the two banks appear separately. The Analysis screen works its fuel-trim figures out of a recorded drive rather than a single moment.
The Dashboard shows Short fuel trim and Long fuel trim, Air flow, Manifold pressure, Intake air temp, Coolant temp, Throttle position, Accelerator pedal, Air/fuel ratio, O2 sensor (rear), O2 sensor current and whether the Fuel system is in closed loop. Record a drive and the Analysis screen gives the total correction At idle, Fuel trim against air flow, and whether the air flow and pressure sensors agree; the Full scan's On-board self-tests list the Oxygen sensor results by bank and sensor. Record before and after a repair and Compare shows the change in short, long and total trim at idle plus which codes are Gone, New or Still there.