P2000high severityPowertrain
NOx Trap Efficiency Below Threshold Bank 1
on 2011 Subaru Impreza 2.5L H4 · 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.
Other Powertrain codes on this vehicle
P0001
Fuel Volume Regulator Control Circuit/Open
P0002
Fuel Volume Regulator Control Circuit Range/Performance
P0003
Fuel Volume Regulator Control Circuit Low
P0004
Fuel Volume Regulator Control Circuit High
P0010
Intake Camshaft Position Actuator Circuit/Open Bank 1
P0011
Intake Camshaft Position Timing Over-Advanced Bank 1
P0012
Intake Camshaft Position Timing Over-Retarded Bank 1
P0013
Exhaust Camshaft Position Actuator Circuit/Open Bank 1
P0014
Exhaust Camshaft Position Timing Over-Advanced Bank 1
P0015
Exhaust Camshaft Position Timing Over-Retarded Bank 1