P0174
P0174 System Too Lean Bank 2
P0174 is the bank 2 version of a lean-condition code. On V-style engines, bank 2 is the side opposite bank 1.
How urgent is P0174?
Lean running can lead to rough idle, hesitation, and misfire damage if ignored.
Common symptoms
- Check engine light
- Rough idle
- Hesitation
- Engine surge
- Misfire under load
Likely causes
- Vacuum leak on bank 2
- MAF sensor issue
- Low fuel pressure
- Exhaust leak
- PCV or intake gasket leak
What to check before replacing parts
1
Compare bank 1 and bank 2 fuel trims
2
Smoke-test intake
3
Inspect intake boots and PCV lines
4
Check fuel pressure
5
Check upstream O2 sensor behavior
Use the code with symptoms
A code points at the system, not always the failed part. Add your vehicle, mileage, symptoms, and whether the check engine light is steady or flashing so the AI diagnostic can narrow the next step.