Lean NOx Trap (LNT) Desulfation Failure
2009-2013 Audi A3 2.0L TDI
Description
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
- Check LNT NOx efficiency before and after desulfation attempt
- Monitor exhaust temperature during desulfation
- Check fuel quality
- Inspect fuel injectors for desulfation function
- 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.
Related Codes
Other Powertrain Codes
- P0001Fuel Volume Regulator Control Circuit/Open
- P0002Fuel Volume Regulator Control Circuit Range/Performance
- P0003Fuel Volume Regulator Control Circuit Low
- P0004Fuel Volume Regulator Control Circuit High
- P0010Intake Camshaft Position Actuator Circuit/Open Bank 1
- P0011Intake Camshaft Position Timing Over-Advanced Bank 1
- P0012Intake Camshaft Position Timing Over-Retarded Bank 1
- P0013Exhaust Camshaft Position Actuator Circuit/Open Bank 1
- P0014Exhaust Camshaft Position Timing Over-Advanced Bank 1
- P0015Exhaust Camshaft Position Timing Over-Retarded Bank 1
P3881 on Other Vehicles
Common Questions
What does code P3881 mean on a 2009-2013 Audi A3?
P3881 stands for "Lean NOx Trap (LNT) Desulfation Failure". The lean NOx trap desulfation process has failed to restore NOx conversion efficiency. The LNT requires periodic high-temperature desulfation to remove sulfur compounds.
What are the symptoms of P3881 on a Audi A3?
Common symptoms of P3881 include: Check Engine Light, Increased NOx emissions, LNT warning, Failed emissions test, Reduced power may occur, Fuel economy decrease from failed desulfation attempts.
What causes P3881 on a 2009-2013 Audi A3?
Common causes of P3881 include: Fuel sulfur content too high, LNT catalyst degradation, Exhaust temperature insufficient for desulfation, Fuel injection issue during desulfation, LNT poisoned beyond recovery.