LIGHTING SYSTEM, Diagnostic DTC:B1244

DTC Code DTC Name
B1244 Light Sensor Circuit Malfunction

DESCRIPTION

The automatic light control sensor detects ambient light. The sensor creates an electrical signal based on the amount of light detected, and sends the signal to the main body ECU (multiplex network body ECU).

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

DTC Code DTC Detection Condition Trouble Area
B1244

Either of the following conditions is met:


  • 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 (multiplex network body ECU)

WIRING DIAGRAM

A01WWTPE51
*a Automatic Light Control Sensor
*b Main Body ECU (Multiplex Network Body ECU)

CAUTION / NOTICE / HINT

Note


  • w/ Door Control Battery:

    As the door control battery is installed between the vehicle battery and main body ECU (multiplex network body ECU), first perform the inspections in On-Vehicle Inspection to confirm that there are no malfunctions in the power source circuit for the main body ECU (multiplex network body ECU) before performing this troubleshooting procedure Click here.

  • Before replacing the main body ECU (multiplex network body ECU), refer to Service Bulletin.

PROCEDURE


  1. READ VALUE USING GTS


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the GTS on.

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

    5. Read the Data List according to the display on the GTS.

      Main Body
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Light Sensor Illuminance Light control sensor illuminance / 0 to 17600 lx Value is output according to ambient light level -
      OK
      Normal condition listed above is displayed.
      Result
      Result Proceed to
      OK A
      NG (for LHD) B
      NG (for RHD) C

    A

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

    B

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

    C

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


    1. Disconnect the F90 automatic light control sensor connector.

    2. Disconnect the E118 main body ECU (multiplex network body ECU) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      E118-21 (CLTE) - F90-2 (CLTE) Always Below 1 Ω
      E118-20 (CLTS) - F90-4 (CLTS) Always Below 1 Ω
      E118-19 (CLTB) - F90-1 (CLTB) Always Below 1 Ω
      E118-21 (CLTE) - Body ground Always 10 kΩ or higher
      E118-20 (CLTS) - Body ground Always 10 kΩ or higher
      E118-19 (CLTB) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. INSPECT MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)


    1. A01WV7HE03
      Text in Illustration
      *a

      Component with harness connected

      (Main Body ECU (Multiplex Network Body ECU))

      Reconnect the E118 main body ECU (multiplex network body ECU) connector.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      E118-19 (CLTB) - E118-21 (CLTE) Engine switch off Below 1 V
      Engine switch on (IG) 11 to 14 V
      Result
      Result Proceed to
      OK A
      NG (for LHD) B
      NG (for RHD) C

    B

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

    C

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

    A

  4. INSPECT AUTOMATIC LIGHT CONTROL SENSOR


    1. A01WTSTE03

      Reconnect the F90 automatic light control sensor connector.

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

    3. A01WV7LE01
      Text in Illustration
      *a

      Component with harness connected

      (Automatic Light Control Sensor)

      Check the waveform.

      OK
      Tester Connection Tool Setting Condition Specified Condition
      F90-2 (CLTE) - F90-4 (CLTS) 2 V/DIV., 10 ms./DIV. Engine switch on (IG), light control switch in AUTO position Correct waveform is as shown

      Tech Tips

      The communication waveform changes according to the surrounding brightness.

      Result
      Result Proceed to
      OK (for LHD) A
      NG (for RHD) B
      NG C

    A

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

    B

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

    C

    REPLACE AUTOMATIC LIGHT CONTROL SENSOR Click here