Reductant Pressure Too Low
The pressure in the SCR reductant (AdBlue/DEF) line is below the calibrated minimum. Without sufficient pressure the dosing module cannot atomise reagent properly, leading to NOx exceedence.
Affected components
- Def pump
- Def pressure sensor
- Def lines
Common causes
- High likelihood: Worn DEF pump
- Medium likelihood: Leak in DEF line
- Medium likelihood: Clogged DEF filter
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
Related codes
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.