p0174
Moderate
Audi · Sedans
System Too Lean Bank 2
Quick Answer
Error code P0174 on your Audi Sedans means: System Too Lean Bank 2. This is usually fixable — see the step-by-step guide below.
Affected Models
Applies to all models
8YB9F5C8D5FW
Likely Causes
  1. Vacuum leak on bank 2 side of the intake
  2. Faulty mass air flow (MAF) sensor reading low
  3. Fuel delivery issue such as low fuel pressure
  4. Cracked or deteriorated intake boot
  5. Faulty bank 2 oxygen sensor providing incorrect feedback
How to Fix It
1
Scan for related codes on both banks to determine if the issue is systemic or bank-specific
2
Perform a smoke test on the intake system focusing on bank 2 vacuum lines
3
Inspect the intake boot between the MAF sensor and throttle body for cracks
4
Test fuel pressure and volume output from the fuel pump
5
Monitor bank 2 oxygen sensor data for abnormal readings
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 boot
Vacuum lines
O2 sensor (bank 2)
Related Error Codes
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