System Too Lean (Bank 2)

Identical mechanism to P0171, just measured on bank 2's oxygen sensor. If you have both P0171 AND P0174 at the same time, that usually means a shared problem — like a leaking intake manifold gasket, dirty MAF, or weak fuel pressure feeding both banks.

Bank 2 LTFT exceeding the lean threshold for sustained operation.

Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.

1. 1Check whether P0171 is also set. Both = shared cause. Just one = bank-specific.
2. 2Compare bank 1 vs bank 2 LTFT. Big split = bank-2 specific issue.
3. 3Smoke-test that side of the intake.

• Same as P0171 — but if ONLY bank 2 is lean, look for bank-2-specific leak (injector, manifold runner, exhaust)

Same range as P0171.