P239D — Diesel Intake Air Flow B Control System Low Air Flow Detected
Same as P239C with the airflow below the threshold when the valve is commanded open - valve does not open fully or the path is restricted.
General code reference. Confirm the definition and diagnostic procedure for your vehicle's year, model and engine. A stored code alone does not identify a failed part.
Affected components
- Diesel intake air flow b
Possible causes to check
These are possible checks, not a ranked diagnosis. Follow the vehicle manufacturer's test procedure before replacing parts.
- Valve does not open fully
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
Sources
Check each reference's vehicle and model-year scope. General background links do not establish which fault is most likely on your vehicle.
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.