DTC B1244: Light Sensor Circuit Malfunction [09/2014 - 03/2019]: 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 Data List according to the display on the Techstream.

   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	Value is output according to ambient light level	-

   Body Electrical > Main Body > Data List 

   Tester Display
   Light Sensor Illuminance

   OK

   Normal condition listed above is displayed.

   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
   O2-21 (CLTE) - P1-2 (CLTE)	Always	Below 1 Ω
   O2-20 (CLTS) - P1-4 (CLTS)	Always	Below 1 Ω
   O2-19 (CLTB) - P1-1 (CLTB)	Always	Below 1 Ω
   O2-21 (CLTE) - Body ground	Always	10 kΩ or higher
   O2-20 (CLTS) - Body ground	Always	10 kΩ or higher
   O2-19 (CLTB) - 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

1. Reconnect the O2 main body ECU (multiplex network body ECU) connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

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

1. Reconnect the P1 automatic light control sensor connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

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

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK

   Tester Connection	Tool Setting	Condition	Specified Condition
   P1-2 (CLTE) - P1-4 (CLTS)	2 V/DIV., 10 ms./DIV.	Engine switch on (IG), light control switch in AUTO position	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 - ]