P0174 Code: System Too Lean (Bank 2)
P0174 means the engine on bank 2 is running lean — the same lean condition as P0171 but on the other cylinder bank.
- Applies to
- All OBD-II vehicles (any make or model)
- Est. repair cost
- $50 – $600
- Time to fix
- 1-3 hours
What it means
Common causes are a vacuum/intake leak, a dirty MAF sensor, or low fuel pressure — often affecting both banks (with P0171). This is a generic OBD-II powertrain code defined in the SAE J2012 standard, so it applies to virtually any 1996-or-newer OBD-II vehicle — cars, trucks, and modern fuel-injected motorcycles — from any manufacturer (Toyota, Honda, Ford and the rest). Read it with any OBD-II scanner; the meaning is the same across brands, though the exact repair can vary by engine.
Symptoms
- Check engine light on
- Rough idle, hesitation, surging
- Poor economy
How to fix it
- 1
Check leaks, MAF and fuel
1. Inspect for vacuum/intake leaks (especially if P0171 is also present). 2. Clean the MAF sensor and check fuel pressure. 3. Repair the cause, then clear the code.
Frequently asked questions
I have P0171 and P0174 together — why?
Both banks lean at once usually points to a shared cause — a big vacuum leak, a dirty MAF, or low fuel pressure — rather than a single sensor.
Last updated July 16, 2026
Guidance only — always consult a qualified professional or the official service manual before carrying out repairs.