Fuel Injector - Pilot Injection Not Learned
The pilot (pre) injection learning routine on a common-rail diesel did not complete successfully. Without learned pilot quantity, combustion noise increases and NOx may rise.
Affected components
- Fuel injector
- High pressure pump
- Control module
Common causes
- High likelihood: Injector flow drift outside learning window
- Medium likelihood: Unstable rail pressure during learning cycle
Possible symptoms
- Check engine light on
- Misfire or rough idle on the affected cylinder
- Increased fuel consumption
- Possible fuel smell or smoke from exhaust
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.