AUTOMATIC HIGH BEAM SYSTEM, Diagnostic DTC:B124B

DTC Code DTC Name
B124B Automatic High Beam System

DESCRIPTION

The main body ECU (multiplex network body ECU) 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

  • Hybrid control system

  • SFI system

  • Vehicle stability control system

  • CAN communication system

  • Pre-crash safety city sensor

  • Main body ECU (multiplex network body ECU)

WIRING DIAGRAM

A004EROE08
*1 Spiral Cable with Sensor Sub-Assembly
*2 Headlight Light Control ECU LH
*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.

    w/ Toyota Safety Sense Click here

    w/o Toyota Safety Sense Click here

  • When replacing the pre-crash safety 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-crash safety city sensor will not match the information from the vehicle and, as a result, a DTC may be output.

  • When the pre-crash safety 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-crash safety city sensor when DTCs related to the items below are output.


  • Wheel speed sensor malfunction

  • Airbag ECU assembly (Yaw rate sensor) malfunction

  • CAN communication lost

PROCEDURE


  1. CHECK FOR DTC


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch 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

    A

    GO TO DIAGNOSTIC TROUBLE CODE CHART Click here

    B

  2. CHECK PRE-CRASH SAFETY SYSTEM


    1. Check that a pre-crash safety system warning is not displayed.

      OK
      Pre-crash safety system warning is not displayed.

    OK

    REPLACE MAIN BODY ECU (MULTIPLEXNETWORK BODY ECU) Click here

    NG

    REPLACE PRE-CRASH SAFETY CITY SENSOR Click here