P2000high severityPowertrain
NOx Trap Efficiency Below Threshold Bank 1
on 1998 Audi A6 2.8L V6 · AWD
What this code means
The NOx storage catalytic converter on bank 1 is not efficiently reducing nitrogen oxides.
Symptoms
- Check engine light
- Failed emissions test
- Reduced fuel economy
Common causes
- Degraded NOx trap
- Sulfur contamination
- Exhaust leak before sensor
- Faulty NOx sensor
Diagnostic steps
- Read freeze frame data
- Check NOx sensor readings upstream and downstream
- Inspect for exhaust leaks
- Perform desulfation procedure if applicable
Repair notes
Replace NOx trap if desulfation fails. Check upstream components for causes of contamination.
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