DTC B1244: Light Sensor Circuit [10/2018 - ]: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the engine switch on (IG).
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 Sensor Fail	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 [09/2014 - ] 

Result: 

NG 

See step  2

1. Disconnect the P1 automatic light control sensor connector.
2. Disconnect the O2 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
   P1-1 (CLTB) - O2-19 (CLTB)	Always	Below 1 Ω
   P1-4 (CLTS) - O2-20 (CLTS)	Always	Below 1 Ω
   P1-2 (CLTE) - O2-21 (CLTE)	Always	Below 1 Ω
   P1-1 (CLTB) or O2-19 (CLTB) - Body ground	Always	10 kΩ or higher
   P1-4 (CLTS) or O2-20 (CLTS) - Body ground	Always	10 kΩ or higher
   P1-2 (CLTE) or O2-21 (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  3

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Connect the O2 main body ECU (multiplex network body ECU) connector.
2. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   O2-19 (CLTB) - O2-21 (CLTE)	Engine switch off	Below 1 V
   	Engine switch on (IG)	11 to 14 V

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [09/2014 - ] 

Result: 

OK 

See step  4

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Connect the P1 automatic light control sensor connector.
2. Connect an oscilloscope to the automatic light control sensor connector.
3. Check the waveform.

   OK

   Tester Connection	Condition	Tool Setting	Specified Condition
   P1-4 (CLTS) - P1-2 (CLTE)	Engine switch on (IG)	2 V/DIV., 10 ms./DIV.	Correct waveform is as shown

   HINT: 

   The communication waveform changes according to the surrounding brightness.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [09/2014 - ] 

Result: 

NG 

REPLACE AUTOMATIC LIGHT CONTROL SENSOR. Refer to  REMOVAL [09/2014 - ]