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

  • SFI system

  • Vehicle stability control system

  • CAN communication system

  • Pre-crash safety city sensor

  • Main body ECU (multiplex network body ECU)

WIRING DIAGRAM

A0048W1E92
*1 Pre-crash Safety City Sensor
*2 Main Body ECU (Multiplex Network Body ECU)
*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.

  • Before replacing the main body ECU (multiplex network body ECU), refer to Service Bulletin.

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 sensor malfunction

  • CAN communication lost

PROCEDURE


  1. CHECK FOR DTC (HEALTH CHECK)


    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

    B

    GO TO OTHER DTC CHART

    A

  2. CHECK PRE-CRASH SAFETY SYSTEM


    1. Check that no pre-crash safety system warnings are displayed.

      OK
      No pre-crash safety system warnings.
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE MAIN BODY ECU (MULTIPLEXNETWORK BODY ECU) Click here

    NG

    GO TO PRE-CRASH SAFETY SYSTEM Click here