Reductant Injection Valve Stuck Closed (Bank 1 Unit 1)
The DEF injection valve at bank 1 unit 1 does not open when commanded — typically crystallised DEF blocks the nozzle, no flow into the SCR.
Affected components
- Reductant injection valve
Common causes
- High likelihood: Nozzle crystallised
- Medium likelihood: Valve seized
- Low likelihood: Carbon or debris buildup preventing free movement
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
- 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.