OBD Guide
ENFRDEESPT

B124A

Automatic High Beam Mirror

B124A is an OBD-II diagnostic trouble code meaning: Automatic High Beam Mirror. Common causes: light sensor malfunction, wiring harness damage. Estimated repair cost: $33–167.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$33–167 (est.)

Symptoms

  • Automatic high beam does not work
  • The system switches the lights incorrectly
  • The warning light on the dashboard is flashing

Causes

  • Light sensor malfunction
  • Wiring harness damage
  • Problems with the system camera
  • Control unit error

How to Fix

  1. Check light sensors for dirt and damage
  2. Inspect the wiring harness for breaks or damage
  3. Check the system camera (if provided)
  4. Scan the system for additional errors
  5. If necessary, replace faulty components

Related codes

B124BB124CU0121

FAQ

What does the B124A code mean?

B124A is an OBD-II diagnostic trouble code that indicates: Automatic High Beam Mirror

What causes a B124A error code?

The most common causes of B124A include: Light sensor malfunction; Wiring harness damage; Problems with the system camera; Control unit error.

How do I fix a B124A diagnostic trouble code?

To fix B124A: Check light sensors for dirt and damage. Inspect the wiring harness for breaks or damage. Check the system camera (if provided). For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B124A?

Limited driving only, diagnose soon

How much does it cost to fix B124A?

The estimated repair cost for B124A is $33–167. Actual cost depends on your vehicle, location, and labor rates.

FRDEESPT

See also: Russian version · NationStat