Trouble code
P0174
System Too Lean (Bank 2)
What P0174 means
Same lean condition as P0171 but on bank 2. Seeing both codes together points to a shared cause rather than a bank-specific one.
Symptoms you may notice
- Rough idle
- Hesitation
- Poor fuel economy
Common causes, cheapest first
- Vacuum leak
- Dirty mass airflow sensor
- Weak fuel pump
- Intake manifold gasket leak
- PCV system leak
Before you buy anythingP0171 and P0174 together almost always mean one shared problem upstream, most often the mass airflow sensor or a leak at the intake, not two separate faults.
What to do next
- Confirm the code with your own scan tool, or have it read free at a chain parts store.
- Decode your VIN so you know your exact engine and build date.
- Work down the causes above from cheapest to most expensive.
- Search NHTSA for a recall or service bulletin covering this symptom on your vehicle.
- Read the engine buying guide before ordering.
P0174 is a generic OBD-II code, standardized across every make and model sold in the US from 1996 onward. The meaning is the same on any vehicle; the specific part and its location are not.
Parts
Parts commonly needed for P0174
These go to Amazon. We earn a commission if you buy, at no extra cost to you — see our affiliate disclosure. Which one you actually need depends on diagnosis — read the note above first.
Confirm fitment against your VIN on the listing page before ordering. A part that matches your year and model can still be wrong for your build date or engine code.