LIGHTING SYSTEM, Diagnostic DTC:B1244

DTC Code DTC Name
B1244 Light Sensor Circuit Malfunction

DESCRIPTION

The automatic light control sensor detects ambient light, converts it into an electrical signal, and outputs it 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. DTC Detecting Condition Trouble Area
B1244

  • Malfunction in automatic light control sensor

  • Open or short in automatic light control sensor circuit

  • Automatic light control sensor

  • Harness or connector

  • Main body ECU (multiplex network body ECU)

WIRING DIAGRAM

A005D9QE55
*a Automatic Light Control Sensor
*b Main Body ECU (Multiplex Network Body ECU)

PROCEDURE


  1. READ VALUE USING GTS


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Body Electrical / Main Body / Data List.

    5. Read the display on the GTS.

      Main Body
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Illumination Rate Illumination rate information/0 ms to 2162.65 ms Value is output according to ambient light levels Value changes according to ambient light
      OK
      Normal condition listed above is displayed.

    OK

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

    NG

  2. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - AUTOMATIC LIGHT CONTROL SENSOR)


    1. Disconnect the I1 automatic light control sensor connector.

    2. Disconnect the L7 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
      L7-22 (CLTE) - I1-6 (CLTE) Always Below 1 Ω
      L7-21 (CLTS) - I1-4 (CLTS) Always Below 1 Ω
      L7-20 (CLTB) - I1-3 (CLTB) Always Below 1 Ω
      L7-22 (CLTE) - Body ground Always 10 kΩ or higher
      L7-21 (CLTS) - Body ground Always 10 kΩ or higher
      L7-20 (CLTB) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. INSPECT MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)


    1. A005E3TE03
      Text in Illustration
      *a

      Component with harness connected

      (Main Body ECU (Multiplex Network Body ECU))

      Reconnect the L7 main body ECU (multiplex network body ECU) connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      L7-20 (CLTB) - L7-22 (CLTE) Power switch off Below 1 V
      Power switch on (IG) 11 to 14 V
      Standard Resistance
      Tester Connection Condition Specified Condition
      L7-22 (CLTE) - Body ground Always Below 1 Ω

    NG

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

    OK

  4. INSPECT AUTOMATIC LIGHT CONTROL SENSOR


    1. A005CR7E01

      Reconnect the I1 automatic light control sensor connector.

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

      Text in Illustration
      *a

      Component with harness connected

      (Automatic Light Control Sensor)
    3. A005CZME30

      Check the waveform.

      OK
      Tester Connection Tool Setting Condition Specified Condition
      I1-6 (CLTE) - I1-4 (CLTS) 5 V/DIV., 5 ms./DIV. Power switch on (IG), light control switch in AUTO position Correct waveform is as shown

      Tech Tips

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


    OK

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

    NG

    REPLACE AUTOMATIC LIGHT CONTROL SENSOR Click here