AUTOMATIC HIGH BEAM SYSTEM, Diagnostic DTC:B124B

DTC Code DTC Name
B124B Automatic High Beam System

DESCRIPTION

The main body ECU (instrument panel junction block assembly) determines the status of the automatic high beam system based on the automatic high beam system signal from the pre-crash safety city sensor.

DTC No. DTC Detection Condition Trouble Area
B124B Automatic high beam system malfunction

  • Pre-crash safety system

  • Lane departure alert system

  • SFI system

  • Vehicle stability control system

  • CAN communication system

  • Pre-crash safety city sensor

  • Main body ECU (instrument panel junction block assembly)

WIRING DIAGRAM

A005479E01
*1 Pre-crash Safety City Sensor
*2 Main Body ECU (Instrument Panel Junction Block Assembly)
*3 CAN Communication Line

CAUTION / NOTICE / HINT

Note

First perform the communication function inspections in How to Proceed with Troubleshooting to confirm that there are no CAN communication malfunctions before troubleshooting this problem Click here.

Tech Tips

This DTC is output simultaneously from the pre-crash safety city sensor when DTCs related to the items below are output.


  • Wheel speed sensor malfunction

  • Yaw rate sensor malfunction

  • Steering angle sensor system malfunction

  • CAN communication lost

PROCEDURE


  1. CHECK FOR DTC


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Enter the following menus: System Select / Health Check

    5. Check for DTCs.

      Result
      Result Proceed to
      Only DTC B124B is output A
      DTC B124B is output at the same time B

    B

    GO TO DIAGNOSTIC TROUBLE CODE CHART Click here

    A

  2. CHECK PRE-CRASH SAFETY SYSTEM


    1. Check if a pre-crash safety system warning message is displayed on the combination meter assembly.

      OK
      No pre-crash safety system warning messages are displayed.

    OK

    REPLACE MAIN BODY ECU (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

    NG

    GO TO PRE-CRASH SAFETY SYSTEM Click here