p0174
Moderate
BMW · SUVs
System Too Lean Bank 2
Quick Answer
Error code P0174 on your BMW SUVs means: System Too Lean Bank 2. This is usually fixable — see the step-by-step guide below.
Affected Models
Likely Causes
  1. Vacuum leak on bank 2 intake runners
  2. Failing mass airflow sensor underreporting airflow
  3. Leaking intake manifold gasket on bank 2
  4. Partially clogged bank 2 fuel injectors
  5. Low fuel pressure from degraded fuel pump
How to Fix It
1
Perform a smoke test on the intake system focusing on bank 2
2
Clean or replace the MAF sensor
3
Monitor fuel trim data with a scan tool at idle and under load
4
Measure fuel system pressure at the rail
5
Inspect bank 2 fuel injectors and replace if clogged
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
Parts You May Need
MAF sensor
Intake manifold gasket
Fuel injectors
Vacuum hoses
Related Error Codes
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