Reductant Injection Air Pressure Leakage
A leak has been detected in the air-assist branch of the DEF system — pressure decays faster than allowed when the air pump shuts off.
Affected components
- Reductant air line
- Reductant air pressure control valve
Common causes
- High likelihood: Cracked air line or fitting
- Medium likelihood: Air pressure control valve seat leaks
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
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.