LIGHTING SYSTEM, Diagnostic DTC:B1244

DTC Code DTC Name
B1244 Light Sensor Circuit Malfunction

DESCRIPTION

The automatic light control sensor detects ambient light. The sensor creates an electrical signal based on the amount of light detected, and sends the signal to the main body ECU (multiplex network body ECU). The main body ECU (multiplex network body ECU) turns on or off the headlights and taillights according to the signal.

DTC No. Detection Item DTC Detection Condition Trouble Area DTC Output from Note
B1244 Light Sensor Circuit Malfunction

    Detection condition:

  • Power switch on (IG)


    Malfunction status:

  • Either of the following conditions is met:


    • Malfunction in automatic light control sensor

    • Open or short in automatic light control sensor circuit


    Malfunction duration:

  • 5 seconds or more

  • Harness or connector

  • Automatic light control sensor

  • Main body ECU (multiplex network body ECU)

 Main body ECU (multiplex network body ECU) -

WIRING DIAGRAM

B004TDYE14
*a Automatic Light Control Sensor
*b Main Body ECU (Multiplex Network Body ECU)

CAUTION / NOTICE / HINT

Note

Before replacing the main body ECU (multiplex network body ECU), refer to Service Bulletin.

PROCEDURE


  1. CHECK FOR DTC


    1. Clear the DTCs.

      Click here


      Body Electrical > Main Body > Clear DTCs

    2. Turn the power switch on (IG) and wait for at least 5 seconds or more.

    3. Check for DTCs.

      Click here


      Body Electrical > Main Body > Trouble Codes
      OK
      DTC B1244 is not output.
      Result
      Proceed to
      OK
      NG

    OK

    USE SIMULATION METHOD TO CHECK Click here

    NG

  2. READ VALUE USING GTS


    1. Using the GTS, read the Data List.

      Click here

    2. According to the display on the GTS, read the Data List and check that the value of Light Sensor Illuminance changes while performing the following:


      1. Turn the light control switch to the AUTO position.

      2. Cover the automatic light control sensor with an opaque object.

      3. 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 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

    OK

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) Click here

    NG

  3. CHECK AUTOMATIC LIGHT CONTROL SENSOR


    1. Using an oscilloscope, check the waveform.

      B004UNYC04
      *a

      Component with harness connected

      (Main Body ECU [Multiplex Network Body ECU])

      		 *b Waveform
      Measurement Condition
      Tester Connection Condition Tool Setting Specified Condition
      G12-24 (CLTS) - Body ground Power switch on (IG), material which blocks light used to cover and then uncover top of automatic light control sensor 2 V/DIV., 10 ms./DIV. Pulse generation

      Tech Tips

      The communication waveform changes according to the surrounding brightness.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) Click here

    NG

  4. CHECK MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)


    1. B004WDDC09
      *a

      Component with harness connected

      (Main Body ECU [Multiplex Network Body ECU])

      Disconnect the G16 automatic light control sensor connector.

    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      G12-23 (CLTB) - G12-25 (CLTE) Power switch off Below 1 V
      Power switch on (IG) 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) Click here

    OK

  5. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU [MULTIPLEX NETWORK BODY ECU] - AUTOMATIC LIGHT CONTROL SENSOR)


    1. Disconnect the G12 main body ECU (multiplex network body ECU) connector.

    2. Disconnect the G16 automatic light control sensor connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      G12-23 (CLTB) - G16-1 (CLTB) Always Below 1 Ω
      G12-24 (CLTS) - G16-4 (CLTS) Always Below 1 Ω
      G12-25 (CLTE) - G16-2 (CLTE) Always Below 1 Ω
      G12-23 (CLTB) or G16-1 (CLTB) - Body ground Always 10 kΩ or higher
      G12-24 (CLTS) or G16-4 (CLTS) - Body ground Always 10 kΩ or higher
      G12-25 (CLTE) or G16-2 (CLTE) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE AUTOMATIC LIGHT CONTROL SENSOR Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR