Diagnostic Trouble Code
P0174 — System Too Lean Bank 2
System Too Lean Bank 2
Definition
Identical to P0171 but on Bank 2. The air-fuel mixture is running too lean on the second bank of cylinders. When both P0171 and P0174 are present simultaneously, the cause is typically a shared component (MAF sensor, fuel pressure, large vacuum leak).
Common Causes
- Vacuum leak affecting both banks
- Dirty or failing MAF sensor
- Low fuel pressure (weak pump, clogged filter)
- Large intake manifold gasket leak
- PCV system malfunction