Toyota Prius: Automatic High Beam System

Toyota Prius (XW60) 2023-2025 Service Manual / ADAS/AD / Advanced Driver Assistance System / Automatic High Beam System

Parts Location
How To Proceed With Troubleshooting
Problem Symptoms Table
Automatic High Beam Switch Circuit
Automatic High Beam Switch Indicator does not Come ON

Parts Location

PARTS LOCATION

ILLUSTRATION

*1	HEADLIGHT ASSEMBLY LH	*2	HEADLIGHT ASSEMBLY RH
*3	MILLIMETER WAVE RADAR SENSOR ASSEMBLY	*4	FORWARD RECOGNITION CAMERA
*5	NO. 2 SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY)	-	-

ILLUSTRATION

*1	TURN SIGNAL SWITCH	*2	STEERING WHEEL SWITCH HOUSING
*3	AUTOMATIC LIGHT CONTROL SENSOR	*4	COMBINATION METER ASSEMBLY
*5	MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)	*6	POWER DISTRIBUTION BOX ASSEMBLY - ECU-B NO. 2 FUSE
*7	DLC3	*8	AUTO HIGH BEAM SWITCH
*9	STEERING SENSOR	*10	AIRBAG ECU ASSEMBLY
*11	HYBRID Toyota Prius Vehicle CONTROL ECU	-	-

How To Proceed With Troubleshooting

CAUTION / NOTICE / HINT

HINT:

Use the following procedure to troubleshoot the automatic high beam system.
*: Use the GTS.

PROCEDURE

1.	Toyota Prius Vehicle BROUGHT TO WORKSHOP

2.	CUSTOMER PROBLEM ANALYSIS

HINT:

In troubleshooting, confirm that the problem symptoms have been accurately identified. Preconceptions should be discarded in order to make an accurate judgment. To clearly understand what the problem symptoms are, it is extremely important to ask the customer about the problem and the conditions at the time the malfunction occurred.
Gather as much information as possible for reference. Past problems that seem unrelated may also help in some cases.

The following 5 items are important points for problem analysis:

What	Toyota Prius Vehicle model, system name
When	Date, time, occurrence frequency
Where	Road conditions
Under what conditions?	Driving conditions, weather conditions
How did it happen?	Problem symptoms

PRE-CHECK

(a) Measure the auxiliary battery voltage with the ignition switch off.

Standard Voltage:

11 to 14 V

If the voltage is below 11 V, recharge or replace the auxiliary battery before proceeding to the next step.

(b) Check the fuses and relays.

(c) Check the connector connections and terminals to make sure that there are no abnormalities such as loose connections, deformation, etc.

4.	CHECK COMMUNICATION FUNCTION OF CAN COMMUNICATION SYSTEM*

(a) Using the GTS, check for CAN communication system DTCs.

Click here

Result	Proceed to
CAN DTCs are not output	A
CAN DTCs are output	B

GO TO CAN COMMUNICATION SYSTEM

5.	CHECK FOR DTC*

(a) Check for DTCs.

Body Electrical > Main Body > Trouble Codes

Result	Proceed to
DTCs are not output	A
DTCs are output	B

GO TO DIAGNOSTIC TROUBLE CODE CHART

6.	CHECK FOR DTC*

(a) Check for DTCs.

Chassis > Front Recognition Camera > Trouble Codes

Result	Proceed to
DTCs are not output	A
DTCs are output	B

GO TO DIAGNOSTIC TROUBLE CODE CHART

7.	CHECK Toyota Prius Vehicle CONTROL HISTORY*

(a) Using the GTS, check for Vehicle Control History (RoB).

Chassis > Front Recognition Camera > Utility

Tester Display
Toyota Prius Vehicle Control History (RoB)

NOTICE:

Make sure to record the output Vehicle Control History.

Result	Proceed to
Toyota Prius Vehicle Control History codes are not output	A
Vehicle Control History codes are output	B

GO TO Toyota Prius Vehicle CONTROL HISTORY

8.	PROBLEM SYMPTOMS TABLE

(a) Refer to Problem Symptoms Table.

Click here

Result	Proceed to
Fault is not listed in Problem Symptoms Table	A
Fault is listed in Problem Symptoms Table	B

GO TO PROBLEM SYMPTOMS TABLE

9.	OVERALL ANALYSIS AND TROUBLESHOOTING*

(a) Operation Check.

Click here

(b) Terminals of ECU.

Click here

(d) On-Toyota Prius vehicle Inspection.

(e) Inspection.

10.	ADJUST, REPAIR OR REPLACE

11.	CONFIRMATION TEST

END

Problem Symptoms Table

PROBLEM SYMPTOMS TABLE

NOTICE:

When replacing the forward recognition camera, replace it with a new one. If a forward recognition camera which was installed to another vehicle is used, the information stored in the forward recognition camera will not match the information from the Toyota Prius vehicle and a DTC may be stored.
When the forward recognition camera has been replaced with a new one, make sure to clear all stored vehicle control history of each system and the forward recognition camera beam axis alignment data.
HINT:

Forward recognition camera beam axis alignment can be performed by using "One Time Recognition", "Driving Adjustment" or "Camera Axis Adjustment Value Write".

One Time Recognition: Click here

Driving Adjustment: Click here

Camera Axis Adjustment Value Write: Click here
If the forward recognition camera has been replaced with a new one, make sure to perform Software Version Confirmation.
Click here
When replacing the millimeter wave radar sensor assembly, always replace it with a new one. If a millimeter wave radar sensor assembly which was installed to another Toyota Prius vehicle is used, the information stored in the millimeter wave radar sensor assembly will not match the information from the vehicle and a DTC may be stored.
When the millimeter wave radar sensor assembly has been replaced with a new one, it is necessary to perform millimeter wave radar sensor assembly beam axis alignment and to clear the Toyota Prius vehicle control history. Before performing the Driving Adjustment, make sure to read Before Starting Driving Adjustment.
HINT:

Beam axis alignment of the millimeter wave radar sensor assembly can be performed using either Triangle Target, Flat Surface Target or Driving Adjustment.

Triangle Target: Click here

Flat Surface Target: Click here

Driving Adjustment: Click here
When replacing the combination meter assembly, always replace it with a new one. If a combination meter assembly which was installed to another Toyota Prius vehicle is used, the information stored in it will not match the information from the vehicle and a DTC may be stored.
When replacing the forward recognition camera and combination meter assembly, update the ECU security key.
Click here

HINT:

Use the table below to help determine the cause of problem symptoms. If multiple suspected areas are listed, the potential causes of the symptoms are listed in order of probability in the "Suspected Area" column of the table. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.

Automatic High Beam System

Symptom	Suspected Area	Link
Automatic high beam indicator on the combination meter assembly does not illuminate	Check operating conditions
	Meter/gauge system
	Automatic high beam switch circuit
	Headlight dimmer switch circuit
	Combination meter assembly
	Forward recognition camera
	Main body ECU (Multiplex network body ECU)
Automatic high beam system does not operate	Check operating conditions
	Check that the low beams and high beams operate manually	-
	Check automatic light control system operation
	Automatic high beam switch circuit
	Headlight dimmer switch circuit
	Forward recognition camera
	Millimeter wave radar sensor assembly
	Main body ECU (Multiplex network body ECU)
Automatic high beam switch indicator does not come ON	Refer to "Automatic High Beam Switch Indicator does not Come ON"

Automatic High Beam Switch Circuit

DESCRIPTION

The main body ECU (multiplex network body ECU) detects the ON/OFF signal of the auto high beam switch.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Before replacing the main body ECU (multiplex network body ECU), refer to Registration.

Click here

PROCEDURE

1.	READ VALUE USING GTS

(a) Read the Data List according to the display on the GTS.

Body Electrical > Main Body > Data List

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

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Auto High Beam Main Switch

Auto high beam switch signal

OFF or ON

OFF: Auto high beam switch not pressed

ON: Auto high beam switch pressed

Body Electrical > Main Body > Data List

Tester Display
Auto High Beam Main Switch

OK:

Normal conditions listed above are displayed.

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

2.	INSPECT AUTO HIGH BEAM SWITCH

Click here

REPLACE AUTO HIGH BEAM SWITCH

3.	CHECK HARNESS AND CONNECTOR (AUTO HIGH BEAM SWITCH - MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) AND BODY GROUND)

(a) Disconnect the K17 main body ECU (multiplex network body ECU) connector.

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

Standard Resistance:

Click Location & Routing(K77,K17) Click Connector(K77) Click Connector(K17)

Tester Connection	Condition	Specified Condition
K77-5 ( B) - K17-14 (AHBI)	Always	Below 1 Ω
K77-5 ( B) or K17-14 (AHBI) - Body ground	Always	10 kΩ or higher
K77-2 (E) - Body ground	Always	Below 1 Ω

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

REPAIR OR REPLACE HARNESS OR CONNECTOR

Automatic High Beam Switch Indicator does not Come ON

DESCRIPTION

When the automatic high beam system is on, the main body ECU (multiplex network body ECU) illuminates the auto high beam switch indicator.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following procedure.
Before replacing the main body ECU (multiplex network body ECU), refer to Registration.
Click here