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 (driver side junction block assembly). The main body ECU (driver side junction block assembly) 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 (driver side junction block assembly)

WIRING DIAGRAM

A01EK0UE50

INSPECTION PROCEDURE

PROCEDURE


  1. READ VALUE USING GTS


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Select the following menu items: 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 Info Illumination rate information/0 ms to 99.99 ms Value is output according to ambient light levels -
      OK
      Normal condition listed above is displayed.

    NG

    CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - AUTOMATIC LIGHT CONTROL SENSOR) Click here

    OK

    REPLACE MAIN BODY ECU (DRIVER SIDE JUNCTION BLOCK ASSEMBLY) Click here

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


    1. Disconnect the F4 automatic light control sensor connector.

    2. Disconnect the D49 main body ECU (driver side junction block assembly) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      D49-18 (CLTE) - F4-3 (CLTE) Always Below 1 Ω
      D49-19 (CLTS) - F4-5 (CLTS) Always Below 1 Ω
      D49-20 (CLTB) - F4-6 (CLTB) Always Below 1 Ω
      D49-18 (CLTE) - Body ground Always 10 kΩ or higher
      D49-19 (CLTS) - Body ground Always 10 kΩ or higher
      D49-20 (CLTB) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. INSPECT MAIN BODY ECU (DRIVER SIDE JUNCTION BLOCK ASSEMBLY)


    1. Reconnect the D49 main body ECU (driver side junction block assembly) connector.

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

      A01ELBSE07
      Text in Illustration
      *1

      Component with harness connected

      (Main Body ECU (Driver Side Junction Block Assembly))

      		 - -
      Standard Voltage
      Tester Connection Condition Specified Condition
      D49-20 (CLTB) - D49-18 (CLTE) Ignition switch off Below 1 V
      Ignition switch ON 11 to 14 V
      Standard Resistance
      Tester Connection Condition Specified Condition
      D49-18 (CLTE) - Body ground Always Below 1 Ω

    NG

    REPLACE MAIN BODY ECU (DRIVER SIDE JUNCTION BLOCK ASSEMBLY) Click here

    OK

  4. INSPECT AUTOMATIC LIGHT CONTROL SENSOR


    1. A01EJD0E02

      Reconnect the F4 automatic light control sensor connector.

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

      Text in Illustration
      *1

      Component with harness connected

      (Automatic Light Control Sensor)
    3. A01EM0OE01

      Check the waveform.

      OK
      Tester Connection Tool Setting Condition Specified Condition
      F4-3 (CLTE) - F4-5 (CLTS) 5 V/DIV., 5 ms./DIV. Ignition switch ON, light control switch in AUTO position Correct waveform is as shown

      Tech Tips

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


    NG

    REPLACE AUTOMATIC LIGHT CONTROL SENSOR Click here

    OK

    REPLACE MAIN BODY ECU (DRIVER SIDE JUNCTION BLOCK ASSEMBLY) Click here