DTC B1244: Light Sensor Circuit Malfunction: Procedure

1. Clear the DTCs. Refer to DTC CHECK / CLEAR .
2. Check for DTCs. Refer to DTC CHECK / CLEAR .

   OK

   DTC B1244 is not output.

NG → See step   2 

OK → See step   8 

1. Connect the Techstream to the DLC3.
2. Turn the power 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.
   MAIN BODY
   
   

   Techstream Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   Illumination Rate Info	Illumination rate information/ 0 to 2162.65 ms	Value output according to ambient light levels	-

   OK

   Normal conditions listed above are displayed.

NG → See step   3 

OK → See step   6 

1. Disconnect the D1 automatic light control sensor connector.
2. Disconnect the C25 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
   D1-3 (CLTB) - C25-20 (CLTB)	Always	Below 1 Ω
   D1-4 (CLTS) - C25-21 (CLTS)	Always	Below 1 Ω
   D1-6 (CLTE) - C25-22 (CLTE)	Always	Below 1 Ω
   D1-3 (CLTB) - Body ground	Always	10 kΩ or higher
   D1-4 (CLTS) - Body ground	Always	10 kΩ or higher
   D1-6 (CLTE) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

Fig 1: Measuring Voltage Of Main Body ECU (multiplex Network Body ECU) Connector

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Reconnect the 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	Switch Condition	Specified Condition
   C25-20 (CLTB) - C25-22 (CLTE)	Power switch on (IG)	11 to 14 V
   	Power switch off	Below 1 V

   TEXT IN ILLUSTRATION
   
   

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

NG → See step   6 

OK: Go to next step 

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

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Connect an oscilloscope to the automatic light control sensor connector.
3. Check the waveform.

   OK

   Tester Connection	Tool Setting	Switch Condition	Specified Condition
   D1-4 (CLTS) - D1-6 (CLTE)	5 V/DIV., 5 ms./DIV.	Power switch on (IG) and light control switch in AUTO position	Correct waveform is as shown

   HINT: 

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

   TEXT IN ILLUSTRATION
   
   

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

NG → See step   7 

OK → See step   6