OBD-II code guide
P0174 System Too Lean Bank 2
P0174 means the engine computer is adding extra fuel because bank 2 is running lean.
What it means
Bank 2 has too much air, not enough fuel, or sensor data suggesting a lean condition.
Common symptoms
- Check engine light
- Rough idle
- Hesitation
- Lean codes on both banks
- Whistling from intake
Likely causes
- Vacuum leak
- Dirty or inaccurate MAF sensor
- Low fuel pressure
- Exhaust leak
- PCV or intake hose leak
First checks
- Look for P0171 with P0174.
- Inspect intake tubing and vacuum hoses.
- Check fuel pressure if both banks are lean.
- Do not assume the oxygen sensor is the cause.