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2010 AUDI A3
2.0L TDI I4•FWD•AUTOMATIC•diesel•turbo
5 active safety recalls on this vehicle — view recalls
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Repairs0Labor514Torque4430Fluid7DTC767Battery1Maintenance0Recalls5
P3881high severityPowertrain

Lean NOx Trap (LNT) Desulfation Failure

on 2010 Audi A3 2.0L TDI I4 · FWD

What this code means

The lean NOx trap desulfation process has failed to restore NOx conversion efficiency. The LNT requires periodic high-temperature desulfation to remove sulfur compounds.

Symptoms

  • Check Engine Light
  • Increased NOx emissions
  • LNT warning
  • Failed emissions test
  • Reduced power may occur
  • Fuel economy decrease from failed desulfation attempts

Common causes

  • Fuel sulfur content too high
  • LNT catalyst degradation
  • Exhaust temperature insufficient for desulfation
  • Fuel injection issue during desulfation
  • LNT poisoned beyond recovery

Diagnostic steps

  1. Check LNT NOx efficiency before and after desulfation attempt
  2. Monitor exhaust temperature during desulfation
  3. Check fuel quality
  4. Inspect fuel injectors for desulfation function
  5. Review desulfation attempt history

Repair notes

Attempt forced desulfation at controlled temperatures. Replace LNT if desulfation cannot restore efficiency. Use ultra-low sulfur diesel fuel.

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