OBD-II code · Powertrain (generic, extended)
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.
Is it safe to drive with P239D?
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 open 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
- P239ADiesel Intake Air Flow B Position Sensor Circuit Intermittent or Erratic
- P239BDiesel Intake Air Flow B Control Motor Current Range or Performance
- P239CDiesel Intake Air Flow B Control System High 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
- P23A0O2 Sensor Exhaust Sample Error Bank 1 Sensor 2
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.