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2001 AUDI A6
3.0L V6•AWD•AUTOMATIC•gas•AVK
7 active safety recalls on this vehicle — view recalls
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Repairs0Labor501Torque2211Fluid10DTC900Battery1Maintenance0Recalls7
P1128moderate severityPowertrain

Long Term Fuel Trim System Too Lean Bank 1

on 2001 Audi A6 3.0L V6 · AWD

What this code means

The ECU detected that the long-term fuel trim for Bank 1 has reached the maximum lean correction limit. The engine is not receiving enough fuel relative to the air charge, and the system cannot add more fuel.

Symptoms

  • Check Engine Light
  • Rough idle
  • Hesitation on acceleration
  • Lean misfire
  • Poor fuel economy

Common causes

  • Vacuum leak on intake side
  • Weak fuel pump
  • Clogged fuel injectors
  • MAF sensor under-reading
  • Intake manifold gasket leak

Diagnostic steps

  1. Perform smoke test for vacuum leaks
  2. Monitor fuel trim values
  3. Test fuel pressure
  4. Clean or test MAF sensor
  5. Inspect intake manifold gasket

Repair notes

Repair vacuum leaks first; then address fuel delivery issues if trims remain lean.

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🔧 Database maintained under the daily editorial review of Chris Hackleman · Master Technician · 20+ years and Jeff Moore · Master Mechanic · 20+ years. Spot an error? Use the Help link above — a human reads every report.
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