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 on or off the headlights and taillights according to the signal.

DTC No. DTC Detection Condition Trouble Area
B1244
  • Malfunction in automatic light control sensor.

  • Open or short in automatic light control sensor circuit.


  • Automatic light control sensor

  • Main body ECU

  • Harness or connector

WIRING DIAGRAM

A01VKVPE01
*a Automatic Light Control Sensor
*b Main Body ECU

PROCEDURE


  1. CHECK FOR DTC


    1. Clear the DTCs Click here.

    2. Check for DTCs Click here.

      OK
      DTC B1244 is not output.

    OK
    NG
  2. READ VALUE USING INTELLIGENT TESTER


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the intelligent tester on.

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

    5. According to the display on the intelligent tester, read the Data List.

      Main Body
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Illumination Rate Info

      Illumination rate information/

      0 to 2162.65 ms

      Value output according to ambient light levels -
      OK
      Normal conditions listed above are displayed.

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


    1. Disconnect the F73 automatic light control sensor connector.

    2. Disconnect the F76 main body ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      F73-3 (CLTB) - F76-20 (CLTB) Always Below 1 Ω
      F73-4 (CLTS) - F76-21 (CLTS) Always Below 1 Ω
      F73-5 (CLTE) - F76-22 (CLTE) Always Below 1 Ω
      F73-3 (CLTB) - Body ground Always 10 kΩ or higher
      F73-4 (CLTS) - Body ground Always 10 kΩ or higher
      F73-5 (CLTE) - Body ground Always 10 kΩ or higher

    NG
    OK
  4. CHECK MAIN BODY ECU

    A01VGCWE01
    Text in Illustration
    *a

    Component with harness connected

    (Main Body ECU)


    1. Reconnect the 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
      F76-20 (CLTB) - F76-22 (CLTE) Ignition switch ON 11 to 14 V
      Ignition switch off Below 1 V

    NG
    OK
  5. CHECK AUTOMATIC LIGHT CONTROL SENSOR


    1. A01VL1KE01
      Text in Illustration
      *a

      Component with harness connected

      (Automatic Light Control Sensor)

      Reconnect the automatic light control sensor connector.

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

    3. Check the waveform.

      OK
      Tester Connection Tool Setting Switch Condition Specified Condition
      F73-4 (CLTS) - F73-5 (CLTE) 5 V/DIV., 5 ms./DIV. Ignition switch ON, headlight dimmer switch in AUTO position Correct waveform is as shown

      Tech Tips

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


    OK
    NG