System Too Lean (Bank 2)
The air-fuel ratio on bank 2 is too lean beyond the correction range of the fuel trims.
Common causes
- Vacuum or intake air leak
- Dirty MAF sensor
- Weak fuel pump
- Faulty oxygen sensor
Possible symptoms
- Check Engine Light on
- Rough idle
- Hesitation
- Loss of power
Can I keep driving?
You can drive short distances, but don't put it off: this is a medium-severity fault that can raise fuel use and emissions and, if ignored, damage other parts. Have it looked at soon.
Code breakdown
Frequently asked questions
What does code P0174 mean?
P0174 stands for "System Too Lean (Bank 2)". The air-fuel ratio on bank 2 is too lean beyond the correction range of the fuel trims.
Can I keep driving with code P0174?
You can drive short distances, but don't put it off: this is a medium-severity fault that can raise fuel use and emissions and, if ignored, damage other parts. Have it looked at soon.
How do I diagnose and fix code P0174?
Diagnosis starts with the most common causes, checked in this order: Vacuum or intake air leak; Dirty MAF sensor; Weak fuel pump; Faulty oxygen sensor. Reading live data with an OBD-II tool helps confirm the fault before replacing any parts.
Related codes
- P0100 — Mass or Volume Air Flow Circuit
- P0101 — Mass or Volume Air Flow Circuit Range/Performance
- P0102 — Mass or Volume Air Flow Circuit Low Input
- P0103 — Mass or Volume Air Flow Circuit High Input
- P0104 — Mass or Volume Air Flow Circuit Intermittent
- P0105 — Manifold Absolute Pressure/Barometric Pressure Circuit