DTC B1244: Light Sensor Circuit Malfunction: 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 / 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 ms to 99.99 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 E1 automatic light control sensor connector.
2. Disconnect the D13 main body ECU connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   D13-22 (CLTE) - E1-3 (CLTE)	Always	Below 1 Ω
   D13-21 (CLTS) - E1-5 (CLTS)	Always	Below 1 Ω
   D13-20 (CLTB) - E1-6 (CLTB)	Always	Below 1 Ω
   D13-22 (CLTE) - Body ground	Always	10 kΩ or higher
   D13-21 (CLTS) - Body ground	Always	10 kΩ or higher
   D13-20 (CLTB) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Reconnect the D13 main body ECU connector.
2. Measure the voltage and resistance according to the value(s) in the table below.
   Fig 1: Inspecting Main Body ECU

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   D13-20 (CLTB) - D13-22 (CLTE)	Ignition switch off	Below 1 V
   	Ignition switch ON	11 to 14 V

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   D13-22 (CLTE) - Body ground	Always	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

   *a	Component with harness connected (Main Body ECU)

NG → See step   5 

OK: Go to next step 

1. Reconnect the E1 automatic light control sensor connector.
   Fig 2: Inspecting Automatic Light Control Sensor

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   TEXT IN ILLUSTRATION
   
   

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

2. Connect an oscilloscope to the automatic light control sensor connector.
3. Check the waveform.
   Fig 3: Identifying Waveform Graph

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK

   Tester Connection	Tool Setting	Switch Condition	Specified Condition
   E1-3 (CLTE) - E1-5 (CLTS)	5 V/DIV., 5 ms./DIV.	Ignition switch ON, light control switch in AUTO position	Correct waveform is as shown

   HINT: 

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

NG → See step   6 

OK → See step   5