SCR NOx Catalyst Efficiency Below Threshold (Bank 2)
SCR NOx Catalyst Efficiency Below Threshold (Bank 2): the control module has detected this fault condition.
Affected components
- Scr catalyst
- Nox sensor downstream
Common causes
- High likelihood: SCR catalyst thermally aged
- Medium likelihood: Catalyst poisoning from sulphur or oil ash
Possible symptoms
- Check engine light on
- Failed emissions inspection
- Possibly slightly increased fuel consumption
- Sulfur (rotten egg) smell from exhaust under load
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
- A drive cycle may be required after repair
- Reduced-power or limp mode may occur
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.