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

  • Harness or connector

  • Main body ECU

WIRING DIAGRAM

A01CGAJE12

INSPECTION PROCEDURE

PROCEDURE


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


    1. A01CEJ5E14

      Disconnect the H1 automatic light control sensor connector.

    2. Disconnect the G49 main body ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G49-18 (CLTE) - H1-3 (CLTE) Always Below 1 Ω
      G49-18 (CLTE) - Body ground Always 10 kΩ or higher
      G49-19 (CLTS) - H1-5 (CLTS) Always Below 1 Ω
      G49-19 (CLTS) - Body ground Always 10 kΩ or higher
      G49-20 (CLTB) - H1-6 (CLTB) Always Below 1 Ω
      G49-20 (CLTB) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  2. INSPECT MAIN BODY ECU


    1. A01CEFUE01

      Reconnect the main 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
      G49-20 (CLTB) - G49-18 (CLTE) Engine switch off Below 1 V
      Engine switch on (IG) 11 to 14 V
      Standard Resistance
      Tester Connection Condition Specified Condition
      G49-18 (CLTE) - Body ground Always Below 1 Ω

    NG

    REPLACE MAIN BODY ECU Click here

    OK

  3. INSPECT AUTOMATIC LIGHT CONTROL SENSOR


    1. A01CCE2E03

      Reconnect the automatic light control sensor connector.

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

    3. A01CC7RE01

      Check the waveform.

      OK
      Tester Connection Tool Setting Condition Specified Condition
      H1-3 (CLTE) - H1-5 (CLTS) 5 V/DIV., 5 ms./DIV. Engine switch on (IG), light control switch in AUTO 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 Click here