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p0171
Moderate
Audi · SUVs
System Too Lean Bank 1
Quick Answer
Error code P0171 on your Audi SUVs means: System Too Lean Bank 1. This is usually fixable — see the step-by-step guide below.
Affected Models
Applies to all models
F3FY4M4MNGENGE
Likely Causes
  1. Vacuum leak in intake manifold or associated hoses
  2. Faulty or contaminated mass air flow (MAF) sensor
  3. Weak fuel pump or clogged fuel filter
  4. Dirty or failing fuel injectors
  5. Exhaust leak upstream of the oxygen sensor
How to Fix It
1
Scan for additional codes and review freeze frame data
2
Perform a smoke test on the intake system to locate vacuum leaks
3
Clean or replace the MAF sensor
4
Test fuel pressure at the fuel rail against manufacturer specification
5
Inspect oxygen sensor readings for proper switching behavior
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
Intake manifold gasket
Fuel filter
Related Error Codes
P0174P0300P0302P0420P0430
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