AutoCodes – Lexus – B124A Lexus

B124A Lexus Code - Automatic High Beam Mirror

Quick Answer

This Diagnostic Trouble Code (DTC) is stored when the Main Body ECU (Multiplex Network Body ECU) detects a malfunction in the Forward Recognition Camera. Common causes include Faulty Forward Recognition Camera, Forward Recognition Camera harness is open or shorted, Forward Recognition Camera circuit poor electrical connection. Severity is Low - monitor the vehicle and repair when practical. The vehicle can usually be driven if no severe symptoms are present, but symptoms should be checked before extended driving.

What it means: B124A Lexus indicates Automatic High Beam Mirror.
Common causes: Common causes include Faulty Forward Recognition Camera, Forward Recognition Camera harness is open or shorted, Forward Recognition Camera circuit poor electrical connection.
Severity: Low - monitor the vehicle and repair when practical.
Can I drive?: The vehicle can usually be driven if no severe symptoms are present, but symptoms should be checked before extended driving.

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Code Popularity 471

How popular is this code, among other codes? Low

Repair Importance Level

Low (Monitor) (1 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Nov 19, 2024

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code B124A Lexus Description

This Diagnostic Trouble Code (DTC) is stored when the Main Body ECU (Multiplex Network Body ECU) detects a malfunction in the Forward Recognition Camera.

OBDII Code B124A Lexus - Automatic High Beam Mirror - AutoCodes.com — B124A Lexus Code - Automatic High Beam Mirror

What does this mean?

What are the Possible Causes of the DTC B124A Lexus?

Faulty Forward Recognition Camera
Forward Recognition Camera harness is open or shorted
Forward Recognition Camera circuit poor electrical connection
Faulty Main Body ECU (Multiplex Network Body ECU)

How to Fix the DTC B124A Lexus?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

When replacing the forward recognition camera, always replace it with a new one. If a forward recognition camera that was installed on another vehicle is used, the information stored in the forward recognition camera will not match the information from the vehicle. As a result, a DTC may be stored.
If the forward recognition camera has been replaced with a new one, be sure to perform Recognition Camera/Target Position Memory and Recognition Camera Axis Adjust.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B124A Lexus code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about B124A Lexus Code

1. What does the OBDII code B124A on a Lexus indicate?

- The code B124A on a Lexus indicates a fault in the Automatic High Beam Mirror system, which is part of the vehicle's advanced lighting system designed to automatically adjust the high beam headlights.

2. What symptoms might I notice if my Lexus has the B124A code?

- Symptoms of the B124A code typically include the automatic high beam feature not working, the high beam indicator light might blink or stay on continuously, and there may be an error message displayed on the dashboard.

3. What are common causes of the B124A code in a Lexus?

- Common causes for the B124A code include a malfunctioning automatic high beam sensor, damaged wiring or connectors related to the high beam system, or issues with the vehicleâ€™s onboard computer.

4. How can I troubleshoot the B124A code in my Lexus?

- Troubleshooting the B124A code involves checking the automatic high beam sensor for any obstructions or damage, inspecting the wiring and connectors for damage, and using an OBDII scanner to further diagnose the problem.

5. What repair steps should be taken to fix the B124A code in a Lexus?

- Repair steps might include cleaning or replacing the automatic high beam sensor, repairing or replacing any damaged wiring or connectors, and possibly reprogramming or replacing the vehicleâ€™s computer system if it is found to be faulty.

6. Is it safe to drive my Lexus with the B124A code?

- While it may be safe to drive with this code active, your high beams might not function properly, which could impair your visibility during night driving or in low-light conditions. It is advisable to address the issue promptly for safety.

7. Can I fix the B124A code on my Lexus myself?

- If you have experience with car electronics, you might be able to address simple issues like cleaning the sensor or checking the wiring. However, if the problem involves electrical faults or computer issues, professional service is recommended.

8. What tools are needed to diagnose the B124A code on a Lexus?

- Diagnosing the B124A code typically requires an OBDII scanner that can read Lexus-specific codes, a digital multimeter for testing wiring continuity, and basic hand tools for accessing the sensor and wiring.

9. How often does the B124A code occur in Lexus vehicles?

- The frequency of the B124A code can vary based on model and usage but is generally not very common. Issues may arise due to specific circumstances like sensor blockage or electrical system malfunctions.