Powertrain
Definition only
Lights the check engine lamp
P239C: Diesel Intake Air Flow B Control System High Air Flow Detected
Standardized SAE J2012 code · P23xx — Ignition system and misfire
What does P239C mean?
With diesel intake air flow valve B commanded closed the measured airflow is above the calibrated threshold - valve does not seat or position sensor offset.
The code tells you which monitor failed, not which part is broken. Test before replacing parts.
Common causes
- High Valve does not seat fully
Likelihood is a general estimate across vehicles; your make and model may differ.
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P239C in the community
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