OBD Guide

P2391

Diesel Intake Air Flow B Control Performance

P2391 is an OBD-II diagnostic trouble code meaning: Diesel Intake Air Flow B Control Performance. Common causes: malfunction of the mass air flow sensor (maf), dirty or stuck air control valve. 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
  • Unstable idling
  • Increased fuel consumption
  • Black smoke from the exhaust pipe

Causes

  • Malfunction of the mass air flow sensor (MAF)
  • Dirty or stuck air control valve
  • Open or short circuit in wiring
  • Air filter dirty
  • Malfunction of the engine control unit (ECU)

How to Fix

  1. Check the condition of the air filter
  2. Diagnose the mass air flow sensor and its wiring
  3. Check the air flow control valve for dirt and movement.
  4. Scan the ECU for other errors
  5. If necessary, replace faulty components

Related codes

Error P2391 by Vehicle Brand

FAQ

What does the P2391 code mean?

P2391 is an OBD-II diagnostic trouble code that indicates: Diesel Intake Air Flow B Control Performance

What causes a P2391 error code?

The most common causes of P2391 include: Malfunction of the mass air flow sensor (MAF); Dirty or stuck air control valve; Open or short circuit in wiring; Air filter dirty.

How do I fix a P2391 diagnostic trouble code?

To fix P2391: Check the condition of the air filter. Diagnose the mass air flow sensor and its wiring. Check the air flow control valve for dirt and movement.. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P2391?

Yes, but get it checked soon

How much does it cost to fix P2391?

The estimated repair cost for P2391 is $17–89. Actual cost depends on your vehicle, location, and labor rates.

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