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-collision city sensor.

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

  • Pre-collision system

  • Lane departure alert system

  • SFI system (except 1WW)

  • ECD system (for 1WW)

  • Vehicle stability control system

  • CAN communication system

  • Pre-collision city sensor

  • Main body ECU (instrument panel junction block assembly)

WIRING DIAGRAM

A002NEDE01
*1 Pre-collision City Sensor
*2 Main Body ECU (Instrument Panel Junction Block Assembly)
*3 CAN Communication Line

CAUTION / NOTICE / HINT

Note


  • If the main body ECU (instrument panel junction block assembly) is replaced, refer to the Service Bulletin.

  • 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.

  • When replacing the pre-collision city sensor, replace it with a new one and be sure to initialize the settings. If an ECU which was installed to another vehicle is used, the information stored in the pre-collision city sensor will not match the information from the vehicle and, as a result, a DTC may be output.

  • When the pre-collision city sensor is replaced with a new one or it is removed, camera beam axis learning must be performed.

Tech Tips

This DTC is output simultaneously from the pre-collision 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 (HEALTH CHECK)


    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

    A

  2. CHECK PRE-COLLISION SYSTEM


    1. Check that a pre-collision system Click here.

      OK
      Pre-collision system warning not displayed

    OK

    REPLACE MAIN BODY ECU (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

    NG

    GO TO PRE-COLLISION SYSTEM Click here