LIGHTING (EXT): LIGHTING SYSTEM: B124B; Automatic High Beam System; 2018 - 2020 MY Sienna [11/2017

Last Modified: 04-05-2023	6.11:8.1.0	Doc ID: RM1000000018H93
Model Year Start: 2018	Model: Sienna	Prod Date Range: [11/2017 - ]
Title: LIGHTING (EXT): LIGHTING SYSTEM: B124B; Automatic High Beam System; 2018 - 2020 MY Sienna [11/2017 - ]

DTC

B124B

Automatic High Beam System

DESCRIPTION

The main body ECU determines the status of the automatic high beam system based on the automatic high beam system signal from the forward recognition camera.

DTC No.	DTC Detection Condition	Trouble Area
B124B	Malfunction in automatic high beam system	Forward recognition camera system Pre-collision system SFI system Vehicle stability control system CAN communication system Forward recognition camera Main body ECU

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

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

Click here

HINT:

If the forward recognition camera stores a DTC for a malfunction of any of the following, this DTC will be stored simultaneously.

Speed sensor malfunction
Yaw rate sensor malfunction
Steering sensor malfunction
CAN communication system

PROCEDURE

1.	CHECK FOR DTC (HEALTH CHECK)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(d) Enter the following menus: System Select / Health Check.

(e) Check for DTCs.

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

GO TO OTHER DTC CHART

2.	CHECK FORWARD RECOGNITION CAMERA

(a) Check if a dynamic radar cruise control system, lane departure alert system and pre-collision system warning message are displayed on the combination meter assembly.

Click here

OK:

No dynamic radar cruise control system, lane departure alert system and pre-collision system warning messages are displayed.

REPLACE MAIN BODY ECU

GO TO FORWARD RECOGNITION CAMERA SYSTEM