DTC B1244: Light Sensor Circuit Malfunction: 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. Read the display on the Techstream.
   MAIN BODY
   
   

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   Illumination Rate info	Illumination rate information/0.00 ms to 2162.65 ms	Value is output according to ambient light levels	-

   OK

   Normal condition listed above is displayed.

NG → See step   2 

OK → See step   5 

1. Disconnect the D51 automatic light control sensor connector.
2. Disconnect the D6 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
   D6-22 (CLTE) - D51-3 (CLTE)	Always	Below 1 Ω
   D6-21 (CLTS) - D51-5 (CLTS)	Always	Below 1 Ω
   D6-20 (CLTB) - D51-6 (CLTB)	Always	Below 1 Ω
   D6-22 (CLTE) - Body ground	Always	10 kΩ or higher
   D6-21 (CLTS) - Body ground	Always	10 kΩ or higher
   D6-20 (CLTB) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Reconnect the D6 main body ECU (multiplex network body ECU) connector.
   Fig 1: Measuring Voltage Of Main Body ECU (Multiplex Network Body ECU) Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the voltage and resistance according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   D6-20 (CLTB) - D6-22 (CLTE)	Engine switch off	Below 1 V
   	Engine switch on (IG)	11 to 14 V

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   D6-22 (CLTE) - Body ground	Always	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

   *a	Component with harness connected (Main Body ECU - Multiplex Network Body ECU)

NG → See step   5 

OK: Go to next step 

1. Reconnect the D51 automatic light control sensor connector.
   Fig 2: Identifying Automatic Light Control Sensor Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Connect an oscilloscope to the automatic light control sensor connector.
   TEXT IN ILLUSTRATION
   
   

   *a	Component with harness connected (Automatic Light Control Sensor)

3. Check the waveform.

   OK

   Tester Connection	Tool Setting	Condition	Specified Condition
   D51-3 (CLTE) - D51-5 (CLTS)	5 V/DIV., 5 ms./DIV.	Engine switch on (IG), light control switch in AUTO position	Correct waveform is as shown

   Fig 3: Identifying Correct Waveform

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   HINT: 

   If the ambient light becomes brighter, width A becomes narrower.

NG → See step   6 

OK → See step   5