LIGHTING SYSTEM, Diagnostic DTC:B1244

DTC Code DTC Name
B1244 Light Sensor Circuit Malfunction

DESCRIPTION

The automatic light control sensor*1 or rain sensor*2 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.

  • *1: w/o Rain Sensor

  • *2: w/ Rain Sensor

DTC Code

DTC Detection Condition

Trouble Area

B1244

Either condition is met:

  • w/ Rain Sensor

    • A malfunction in the rain sensor.

    • An open or short in the rain sensor circuit.

  • w/o Rain Sensor

    • A malfunction in the automatic light control sensor.

    • An open or short in the automatic light control sensor circuit.

  • w/ Rain Sensor

    • Rain sensor

    • Windshield wiper relay assembly

  • w/o Rain Sensor

    • Automatic light control sensor

  • Main body ECU (instrument panel junction block assembly)

  • Harness or connector

WIRING DIAGRAM

E344880E02
E344881E02

PROCEDURE

  1. CHECK FOR DTC

    1. Clear the DTCs (Click here).

    2. Check for DTCs (Click here).

      OK

      DTC B1244 output does not occur.

    USE SIMULATION METHOD TO CHECK

    (Click here)

  2. CHECK VEHICLE TYPE

    1. Check vehicle type.

      Table 1. Result

      Result

      Proceed to

      w/ Rain Sensor

      A

      w/o Rain Sensor

      B

    READ VALUE USING INTELLIGENT TESTER (AUTOMATIC LIGHT CONTROL SENSOR)Click here

  3. CHECK AUTOMATIC WIPER FUNCTION

    1. Check the automatic wiper system.

      1. Turn the wiper switch to the AUTO position.

      2. With the rain sensor installed to the windshield, sprinkle water on the windshield around the rain sensor. Check if the wipers operate.

        OK

        The wipers operate.

    GO TO WIPER AND WASHER SYSTEM

    (Click here)

  4. CHECK AUTOMATIC LIGHT CONTROL FUNCTION

    1. Check the automatic light control system.

      1. Turn the light control switch to the AUTO position.

      2. With the rain sensor installed to the windshield, cover the rain sensor with a hand. Check if the headlights operate.

        OK

        The headlights operate.

        Tip:

        The sensitivity of the automatic light control system can be adjusted using the customize function. Make sure that the sensitivity setting is NORMAL before performing this check.

    USE SIMULATION METHOD TO CHECK

    (Click here)

  5. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - WINDSHIELD WIPER RELAY ASSEMBLY)

    1. U123757E02

      Disconnect the H56 windshield wiper relay connector and H80 main body ECU connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      H80-15 (CLTS) - H56-23 (SF)

      Always

      Below 1 Ω

      H80-15 (CLTS) - Body ground

      Always

      10 kΩ or higher
      Table 2. Text in Illustration

      *1

      Front view of wire harness connector

      (to Windshield Wiper Relay)

      *2

      Front view of wire harness connector

      (to Main Body ECU)

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  6. CHECK WINDSHIELD WIPER RELAY ASSEMBLY

    1. E178678E03

      Reconnect the H56 windshield wiper relay connector and H80 main body ECU connector.

    2. Connect an oscilloscope to the rain sensor connector.

    3. Check the waveform.

      OK

      Tester Connection

      Switch Condition

      Specified Condition

      H56-23 (SF) - Body ground

      Ignition switch ON

      Pulse generation (See waveform 1)
      Table 3. Text in Illustration

      *1

      Component with harness connected

      (Windshield Wiper Relay)
      1. E354471E01

        Waveform 1

        Item

        Content

        Tool setting

        5 V/DIV., 10 ms./DIV.
        Tip:

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

        Table 4. Result

        Result

        Proceed to

        OK

        A

        NG (for LHD)

        B

        NG (for RHD)

        C

    REPLACE MAIN BODY ECU (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

    REPLACE WINDSHIELD WIPER RELAY ASSEMBLY

    (Click here)

    REPLACE WINDSHIELD WIPER RELAY ASSEMBLY

    (Click here)

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

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

      Table 5. Main Body

      Tester Display

      Measurement Item/Range

      Normal Condition

      Diagnostic Note

      Illumination Rate Info

      Light control sensor illuminance / 0 to 65535 lx

      Value is output according to ambient light level

      -

      OK

      Normal condition listed above is displayed.

    REPLACE MAIN BODY ECU (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

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

    1. U184811E02

      Disconnect the H80 main body ECU connector.

    2. Disconnect the I2 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

      H80-14 (CLTE) - I2-3 (CLTE)

      Always

      Below 1 Ω

      H80-15 (CLTS) - I2-4 (CLTS)

      Always

      Below 1 Ω

      H80-16 (CLTB) - I2-1 (CLTB)

      Always

      Below 1 Ω

      H80-14 (CLTE) - Body ground

      Always

      10 kΩ or higher

      H80-15 (CLTS) - Body ground

      Always

      10 kΩ or higher

      H80-16 (CLTB) - Body ground

      Always

      10 kΩ or higher
      Table 6. Text in Illustration

      *1

      Front view of wire harness connector

      (to Automatic Light Control Sensor)

      *2

      Front view of wire harness connector

      (to Main Body ECU)

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  9. CHECK MAIN BODY ECU (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

    1. U184810E02

      Remove the main body ECU with the connector(s) still connected.

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

      Standard Voltage

      Tester Connection

      Switch Condition

      Specified Condition

      H80-16 (CLTB) - H80-14 (CLTE)

      Ignition switch off

      Below 1 V

      Ignition switch ON

      11 to 14 V
      Table 7. Text in Illustration

      *1

      Component with harness connected

      (Main Body ECU)

    REPLACE MAIN BODY ECU (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

  10. INSPECT AUTOMATIC LIGHT CONTROL SENSOR

    1. Check the automatic light control sensor (Click here).

    REPLACE MAIN BODY ECU (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

    REPLACE AUTOMATIC LIGHT CONTROL SENSOR

    (Click here)