OBD Guide

B3748

Air Flow Control 3 Feedback Circuit Range/Performance

B3748 is an OBD-II diagnostic trouble code meaning: Air Flow Control 3 Feedback Circuit Range/Performance. Common causes: malfunction of the air flow control solenoid valve (solenoid), mechanical stuck air control valve. Estimated repair cost: $56–167.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$56–167 (est.)

Symptoms

  • Unstable engine operation at idle
  • Reduced engine power
  • Increased fuel consumption
  • Check engine light comes on

Causes

  • Malfunction of the air flow control solenoid valve (solenoid)
  • Mechanical stuck air control valve
  • Damaged wiring harness or poor contact
  • Engine control unit (ECU) malfunction
  • Contamination or wear of VVT system components

How to Fix

  1. Check the condition of the wiring harness and contacts in the control circuit
  2. Check the operation of the solenoid valve (solenoid)
  3. Clean or replace air control valve if necessary
  4. Check VVT system mechanical components for binding or wear.
  5. If necessary, replace faulty components
  6. Reset the error and check the system operation after repair

Related codes

Error B3748 by Vehicle Brand

FAQ

What does the B3748 code mean?

B3748 is an OBD-II diagnostic trouble code that indicates: Air Flow Control 3 Feedback Circuit Range/Performance

What causes a B3748 error code?

The most common causes of B3748 include: Malfunction of the air flow control solenoid valve (solenoid); Mechanical stuck air control valve; Damaged wiring harness or poor contact; Engine control unit (ECU) malfunction.

How do I fix a B3748 diagnostic trouble code?

To fix B3748: Check the condition of the wiring harness and contacts in the control circuit. Check the operation of the solenoid valve (solenoid). Clean or replace air control valve if necessary. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B3748?

Limited driving only, diagnose soon

How much does it cost to fix B3748?

The estimated repair cost for B3748 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat