LIGHTING SYSTEM(for Triple Beam Headlight), 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
B1244 Light Sensor Circuit Malfunction

Either of the following conditions is met:


  • 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

B004GTYE25
*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. 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 Data List according to the display on the GTS.


      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

    OK

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

    NG

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


    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) or P1-2 (CLTE) - Body ground Always 10 kΩ or higher
      O2-20 (CLTS) or P1-4 (CLTS) - Body ground Always 10 kΩ or higher
      O2-19 (CLTB) or P1-1 (CLTB) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


    1. B004E9YC25
      *a

      Component with harness connected

      (Main Body ECU (Multiplex Network Body ECU))

      Reconnect the O2 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 Condition Specified Condition
      O2-19 (CLTB) - O2-21 (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

  4. INSPECT AUTOMATIC LIGHT CONTROL SENSOR


    1. B004GOEC14
      *a

      Component with harness connected

      (Automatic Light Control Sensor)

      Reconnect the P1 automatic light control sensor connector.

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

    3. B004FQSN01

      Check the waveform.

      OK
      Tester Connection Tool Setting Condition Specified Condition
      P1-2 (CLTE) - P1-4 (CLTS) 2 V/DIV., 10 ms./DIV. Power switch on (IG), light control switch in AUTO position Correct waveform is as shown

      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

    REPLACE AUTOMATIC LIGHT CONTROL SENSOR Click here