OBD Guide

P239D

Diesel Intake Air Flow B Control System - Low Air Flow Detected

P239D is an OBD-II diagnostic trouble code meaning: Diesel Intake Air Flow B Control System - Low Air Flow Detected. Common causes: air filter clogged, malfunction of the mass air flow sensor (maf). Estimated repair cost: $17–89.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$17–89 (est.)

Symptoms

  • Reduced engine power
  • Increased fuel consumption
  • Unstable engine idling
  • Black smoke from the exhaust pipe
  • Check Engine Light Illuminates

Causes

  • Air filter clogged
  • Malfunction of the mass air flow sensor (MAF)
  • Problems with the EGR system
  • Air leak in the intake tract
  • Turbocharger malfunction

How to Fix

  1. Check and replace the air filter if necessary
  2. Test and replace the mass air flow sensor if faulty
  3. Check the EGR system for blockage or malfunction
  4. Inspect the intake tract for air leaks
  5. Check the operation of the turbocharger

Related codes

Error P239D by Vehicle Brand

FAQ

What does the P239D code mean?

P239D is an OBD-II diagnostic trouble code that indicates: Diesel Intake Air Flow B Control System - Low Air Flow Detected

What causes a P239D error code?

The most common causes of P239D include: Air filter clogged; Malfunction of the mass air flow sensor (MAF); Problems with the EGR system; Air leak in the intake tract.

How do I fix a P239D diagnostic trouble code?

To fix P239D: Check and replace the air filter if necessary. Test and replace the mass air flow sensor if faulty. Check the EGR system for blockage or malfunction. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P239D?

Yes, but get it checked soon

How much does it cost to fix P239D?

The estimated repair cost for P239D is $17–89. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat