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p0171
Moderate
Volkswagen · Sedans
System Too Lean Bank 1
Quick Answer
Error code P0171 on your Volkswagen Sedans means: System Too Lean Bank 1. This is usually fixable — see the step-by-step guide below.
Affected Models
Applies to all models
3H3CCID7BUBU-GLI3G3G-GTE3DArteon SE 2024Arteon SEL Premium R-Line 2024ID.7 Pro S 2025ID.7 Pro S Plus 2025Jetta GLI Autobahn 2024Jetta GLI S 2024Jetta S 2024Jetta SE 2024Jetta SEL 2024Jetta Sport 2024
Likely Causes
  1. Vacuum leak in intake manifold or hoses
  2. Faulty mass airflow (MAF) sensor
  3. Weak or failing fuel pump
  4. Clogged fuel injectors
  5. Leaking PCV valve or crankcase ventilation system
How to Fix It
1
Use an EVAP/smoke machine to check for vacuum leaks around the intake manifold, throttle body, and vacuum hoses
2
Inspect and clean the MAF sensor with MAF-specific cleaner; replace if readings are out of specification
3
Check fuel pressure at the rail using a fuel pressure gauge and compare to factory spec
4
Test fuel injectors for proper spray pattern and flow rate
5
Inspect PCV valve and crankcase ventilation hoses for cracks or blockages
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
Vacuum hoses
PCV valve
Fuel injectors
Intake manifold gasket
Related Error Codes
P0300P0420P0411P0441P0507
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