Lexus RX (RX 350L, RX450h) 2016-2023 Repair Manual: Automatic High Beam System does not Operate or Operation Indicator does not Illuminate

DESCRIPTION

The main body ECU (multiplex network body ECU) controls the automatic high beam system based on signals received from the forward recognition camera.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

PROCEDURE

1.	READ VALUE USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Chassis / Front Recognition Camera / Data List.

(e) Read the Data List according to the display on the Techstream.

Chassis > Front Recognition Camera > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Front Recognition Camera High Temperature 2	Forward recognition camera condition	Not High Temperature or High Temperature	Not High Temperature: 65°C (149°F) or lower High Temperature: 65°C (149°F) or higher	When "High Temperature" is displayed, the automatic high beam system is temporarily suspended.

Chassis > Front Recognition Camera > Data List

Tester Display
Front Recognition Camera High Temperature 2

OK:

"Not High Temperature" is displayed on the Techstream.

HINT:

If "High Temperature" is displayed, move the vehicle to a cool place and allow the temperature of the forward recognition camera to decrease before continuing with troubleshooting.

NG

END (TEMPORARY SUSPENSION OF AUTOMATIC HIGH BEAM SYSTEM DUE TO HIGH FORWARD RECOGNITION CAMERA TEMPERATURE)

OK

2.	CHECK AUTOMATIC HIGH BEAM INDICATOR LIGHT

(a) Check the operation of the automatic high beam indicator light.

(1) Turn the engine switch on (IG).

(2) Turn the light control switch to the AUTO or head position.

(3) Cover the automatic light control sensor to turn the low beam headlights on.

(4) Move the dimmer switch to the low position.

(5) Press the automatic high beam switch.

OK:

Automatic high beam indicator light illuminate.

NG

GO TO STEP 5

OK

3.	READ VALUE USING TECHSTREAM

*1	Forward Recognition Camera (Automatic High Beam Sensor)
*2	Work Light or Equivalent
*a	100 mm or less

(a) Shine a light on the automatic high beam sensor.

HINT:

If troubleshooting is being performed in a bright area, such as outside on a sunny day, it will not be necessary to perform this step.

(b) Connect the Techstream to the DLC3.

(c) Turn the engine switch on (IG).

(d) Turn the Techstream on.

(e) Enter the following menus: Body Electrical / Main Body / Data List.

(f) Read the Data List according to the display on the Techstream.

Body Electrical > Main Body > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Auto H Beam STS0	Automatic high beam sensor current state	Undetec, CAM NA, No sens, Hlight, Taillgt, Speed, Daytime, Village, Malfunc, Delay, Aim Lmt, SAE Mod, Undefin or LIN Err	Condition can be displayed	-

Body Electrical > Main Body > Data List

Tester Display
Auto H Beam STS0

OK:

"Daytime" is displayed on the Techstream.

NG

REPLACE FORWARD RECOGNITION CAMERA

OK

4.	READ VALUE USING TECHSTREAM

*1	Cardboard or Equivalent Object
*a	150 mm or more
*b	3 mm or more

(a) Cover the automatic high beam sensor with an opaque object, such as cardboard.

(b) Connect the Techstream to the DLC3.

(c) Turn the engine switch on (IG).

(d) Turn the Techstream on.

(e) Enter the following menus: Body Electrical / Main Body / Data List.

(f) Read the Data List according to the display on the Techstream.

HINT:

As it may take time for the values in the Data List to change, wait at least 10 seconds before reading the Data List.

Body Electrical > Main Body > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Auto H Beam STS0	Automatic high beam sensor current state	Undetec, CAM NA, No sens, Hlight, Taillgt, Speed, Daytime, Village, Malfunc, Delay, Aim Lmt, SAE Mod, Undefin or LIN Err	Condition can be displayed	-

Body Electrical > Main Body > Data List

Tester Display
Auto H Beam STS0

OK:

"Speed" is displayed on the Techstream.

OK

USE SIMULATION METHOD TO CHECK

NG

REPLACE FORWARD RECOGNITION CAMERA

5.	READ VALUE USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Main Body / Data List.

(e) Read the Data List according to the display on the Techstream.

Body Electrical > Main Body > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Auto High Beam Main Switch	Automatic high beam switch signal	OFF or ON	OFF: Automatic high beam switch not pressed ON: Automatic high beam switch pressed	-

Body Electrical > Main Body > Data List

Tester Display
Auto High Beam Main Switch

OK:

Normal conditions listed above are displayed.

NG

GO TO STEP 8

OK

6.	READ VALUE USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Main Body / Data List.

(e) Read the Data List according to the display on the Techstream.

Body Electrical > Main Body > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Auto H Beam STS0	Automatic high beam sensor current state	Undetec, CAM NA, No sens, Hlight, Taillgt, Speed, Daytime, Village, Malfunc, Delay, Aim Lmt, SAE Mod, Undefin or LIN Err	Condition can be displayed	-

Body Electrical > Main Body > Data List

Tester Display
Auto H Beam STS0

OK:

"Daytime" or "Speed" is displayed on the Techstream.

NG

REPLACE FORWARD RECOGNITION CAMERA

OK

7.	PERFORM ACTIVE TEST USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Combination Meter / Active Test.

(e) Perform the Active Test according to the display on the Techstream.

Body Electrical > Combination Meter > Active Test

Tester Display	Measurement Item	Control Range	Diagnostic Note
Automatic High Beam Indicator	Automatic high beam indicator light	OFF or ON	-

Body Electrical > Combination Meter > Active Test

Tester Display
Automatic High Beam Indicator

OK:

The automatic high beam indicator light illuminates and turns off.

OK

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

NG

REPLACE COMBINATION METER ASSEMBLY

8.	INSPECT AUTOMATIC HIGH BEAM SWITCH (INTEGRATION CONTROL AND PANEL ASSEMBLY)

(a) Remove the automatic high beam switch (integration control and panel assembly).

Click here

(b) Inspect the automatic high beam switch (integration control and panel assembly).

Click here

NG

REPLACE AUTOMATIC HIGH BEAM SWITCH (INTEGRATION CONTROL AND PANEL ASSEMBLY)

OK

9.	CHECK HARNESS AND CONNECTOR (INTEGRATION CONTROL AND PANEL ASSEMBLY - MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) AND BODY GROUND)

(a) Disconnect the J9 main body ECU (multiplex network body ECU) connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection	Condition	Specified Condition
J83-1 (+B) - J9-23 (AHBI)	Always	Below 1 Ω
J83-1 (+B) or J9-23 (AHBI) - Body ground	Always	10 kΩ or higher
J83-10 (E) - Body ground	Always	Below 1 Ω

OK

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR