OBD-II code · Powertrain (generic, extended)
P239C Diesel Intake Air Flow B Control System High Air Flow Detected
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.
Is it safe to drive with P239C?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyValve does not seat fully
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 1–4 h
- Emissions test
- Likely to fail
- Parts involved
- Diesel Intake Air Flow B
Related codes
- P2399Diesel Intake Air Flow B Position Sensor Circuit High
- P239ADiesel Intake Air Flow B Position Sensor Circuit Intermittent or Erratic
- P239BDiesel Intake Air Flow B Control Motor Current Range or Performance
- P239DDiesel Intake Air Flow B Control System Low Air Flow Detected
- P239EO2 Sensor Out of Range During Deceleration Bank 1 Sensor 2
- P239FO2 Sensor Out of Range During Deceleration Bank 2 Sensor 2
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.