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. The main body ECU turns the headlights and taillights on or off according to the signal.

DTC Code DTC Detection Condition Trouble Area
B1244

  • Malfunction in the automatic light control sensor.

  • Open or short in the automatic light control sensor circuit.

  • Automatic light control sensor

  • Main body ECU (multiplex network body ECU)

  • Harness or connector

WIRING DIAGRAM

A01XIQ5E04
*a Automatic Light Control Sensor
*b Main Body ECU (Multiplex Network Body ECU)

PROCEDURE


  1. CHECK FOR DTC


    1. Clear the DTCs Click here.

    2. Check for DTCs Click here.

      OK
      DTC B1244 output does not occur.

    OK

    USE SIMULATION METHOD TO CHECK Click here

    NG

  2. READ VALUE USING INTELLIGENT TESTER (AUTOMATIC LIGHT CONTROL SENSOR)


    1. Using the intelligent tester, read the Data List Click here.

      Main Body
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Illumination Rate Illumination rate information / 0 ms. to 99.99 ms. Value output according to ambient light levels -
      OK
      Normal condition listed above is displayed.

    OK

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

    NG

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


    1. Disconnect the G64 main body ECU connector.

    2. Disconnect the H19 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
      G64-22 (CLTE) - H19-3 (CLTE) Always Below 1 Ω
      G64-21 (CLTS) - H19-5 (CLTS) Always Below 1 Ω
      G64-20 (CLTB) - H19-6 (CLTB) Always Below 1 Ω
      G64-22 (CLTE) - Body ground Always 10 kΩ or higher
      G64-21 (CLTS) - Body ground Always 10 kΩ or higher
      G64-20 (CLTB) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


    1. A01XDDLE01
      Text in Illustration
      *a

      Component with harness connected

      (Main Body ECU)

      Reconnect the G64 main body ECU connector.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      G64-20 (CLTB) - G64-22 (CLTE) Ignition switch off Below 1 V
      Ignition switch ON and headlight dimmer switch in AUTO position 11 to 14 V

    NG

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

    OK

  5. CHECK AUTOMATIC LIGHT CONTROL SENSOR


    1. A01XFTRE01

      Reconnect the H19 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. A01XD4SE01

      Check the waveform.

      OK
      Tester Connection Tool Setting Switch Condition Specified Condition
      H19-5 (CLTS) - H19-3 (CLTE) 5 V/DIV., 5 ms./DIV.

      Ignition switch ON

      Headlight dimmer switch AUTO Automatic light control sensor covered with a hand → Automatic light control sensor exposed to ambient light

      		 Correct waveform is as shown

      Tech Tips

      When 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