OBD-II CODE / Fuel & air
P0174 · Fuel system too lean, bank 2
The fuel-control system reported a lean condition on bank 2.
Part of the Fuel trim system guide.
Identify bank 2
Bank 2 is the bank without cylinder 1. Use service information to orient yourself on the engine and keep bank numbering separate from sensor position.
Compare both sides
Similar corrections on both sides make a shared intake, air measurement or fuel delivery issue worth checking. A difference concentrated on bank 2 changes which intake, exhaust and fuel checks should come first.
Use the recorded conditions
Capture the engine load and speed where the code set. GM bulletin 21-NA-105 documents an ECM calibration issue on some 2020–2021 Colorado and Canyon trucks with the LGZ engine. Verify bulletin applicability by build date and engine.