NOx Exceedence - Insufficient Reagent Consumption
The aftertreatment system detects elevated NOx emissions while reagent (AdBlue/DEF) consumption is below the expected level. Causes include clogged dosing injector, incorrect dosing rate or tampering.
Affected components
- Def dosing valve
- Scr catalyst
- Nox sensor
Common causes
- High likelihood: Clogged DEF dosing valve
- Medium likelihood: Incorrect dosing calibration
Possible symptoms
- Check engine light or NOx warning on
- AdBlue/DEF level or quality warning
- Possible no-start countdown after ignore period
- Failed emissions inspection (NOx)
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.