DTC B1244: Light Sensor Circuit [12/2021 - 11/2024]: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the Techstream on.
4. Enter the following menus: Body Electrical / Main Body / Clear DTCs.
5. Clear the DTCs.

   Body Electrical > Main Body > Clear DTCs 

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  2

1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON.
3. Wait 5 seconds or more.
4. Turn the Techstream on.
5. Enter the following menus: Body Electrical / Main Body / Trouble Codes.
6. Check for DTCs.

   Body Electrical > Main Body > Trouble Codes 

   OK

   DTC B1244 is not output.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

USE SIMULATION METHOD TO CHECK 

Refer to HOW TO PROCEED WITH TROUBLESHOOTING [11/2018 - ]

Result: 

NG 

See step  3

1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the Techstream on.
4. Enter the following menus: Body Electrical / Main Body / Data List.
5. According to the display on the Techstream, read the Data List and check that the value of Light Sensor Illuminance changes while performing the following:
   1. Cover the automatic light control sensor with an opaque object.
   2. Slowly move the opaque object to uncover and then cover the automatic light control sensor.

      Body Electrical > Main Body > Data List 

      Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
      Light Sensor Illuminance	Light control sensor illuminance	0 to 8191 lx or SensorFail	Value is output according to ambient light level	-

      Body Electrical > Main Body > Data List 

      Tester Display
      Light Sensor Illuminance

      OK

      The value changes according to the amount the automatic light control sensor is covered.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) 

Refer to REMOVAL [12/2021 - 10/2022] , or refer to REMOVAL [10/2022 - 10/2023] , or refer to REMOVAL [10/2023 - ]

Result: 

NG 

See step  4

1. Disconnect the H1 automatic light control sensor connector.
2. Disconnect the G44 main body ECU (multiplex network body ECU) connector.
3. Measure the resistance according to the value (s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   H1-1 (CLTB) - G44-23 (CLTB)	Always	Below 1 Ω
   H1-4 (CLTS) - G44-24 (CLTS)	Always	Below 1 Ω
   H1-2 (CLTE) - G44-25 (CLTE)	Always	Below 1 Ω
   H1-1 (CLTB) or G44-23 (CLTB) - Body ground	Always	10 kΩ or higher
   H1-4 (CLTS) or G44-24 (CLTS) - Body ground	Always	10 kΩ or higher
   H1-2 (CLTE) or G44-25 (CLTE) - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  5

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Measure the voltage according to the value (s) in the table below.

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   G44-23 (CLTB) - G44-25 (CLTE)	Ignition switch off	Below 1 V
   	Ignition switch ON	11 to 14 V

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) 

Refer to REMOVAL [12/2021 - 10/2022] , or refer to REMOVAL [10/2022 - 10/2023] , or refer to REMOVAL [10/2023 - ]

Result: 

OK 

See step  6

1. Inspect the automatic light control sensor.

   Refer to ON-VEHICLE INSPECTION [11/2018 - ]

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) 

Refer to REMOVAL [12/2021 - 10/2022] , or refer to REMOVAL [10/2022 - 10/2023] , or refer to REMOVAL [10/2023 - ]

Result: 

NG 

REPLACE AUTOMATIC LIGHT CONTROL SENSOR 

Refer to REMOVAL [12/2021 - 10/2022] , or refer to REMOVAL [10/2022 - 10/2023] , or refer to REMOVAL [10/2023 - ]