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

The main body ECU (multiplex network body ECU) outputs DTC B1244.

DTC No. Detection Item DTC Detection Condition Trouble Area
B1244 Light Sensor Circuit Malfunction

  • Malfunction in the automatic light control sensor.

  • Open or short in the automatic light control sensor circuit.

  • Automatic light control sensor

  • Main body ECU (multiplex network body ECU)

  • Harness or connector

WIRING DIAGRAM

B006LQ8E13
*a Automatic Light Control Sensor
*b Main Body ECU (Multiplex Network Body ECU)

CAUTION / NOTICE / HINT

Note


  • If the main body ECU (multiplex network body ECU) is replaced, refer to the Service Bulletin.

  • 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.

PROCEDURE


  1. CLEAR DTC


    1. Clear the DTCs.

      Click here


      Body Electrical > Main Body > Clear DTCs
      Result
      Proceed to
      NEXT

    NEXT

  2. CHECK FOR DTC


    1. Turn the engine switch on (IG).

    2. Turn on the headlights using the headlight dimmer switch.

    3. Check for DTCs.

      Click here


      Body Electrical > Main Body > Trouble Codes
      Result
      Proceed to
      DTC B1244 output does not occur
      DTC B1244 output occurs

    DTC B1244 output does not occur

    USE SIMULATION METHOD TO CHECK Click here

    DTC B1244 output occurs

  3. READ VALUE USING GTS (LIGHT SENSOR ILLUMINANCE)


    1. Using the GTS, read the Data List.

      Click here


      Body Electrical > Main Body > Data List
      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 -

      Body Electrical > Main Body > Data List
      Tester Display
      Light Sensor Illuminance
      OK
      The display is as specified in the normal condition column.
      Result
      Proceed to
      OK
      NG

    OK

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

    NG

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


    1. Disconnect the G63 main body ECU (multiplex network body ECU) connector.

    2. Disconnect the H1 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
      G63-21 (CLTE) - H1-2 (CLTE) Always Below 1 Ω
      G63-19 (CLTB) - H1-1 (CLTB) Always Below 1 Ω
      G63-20 (CLTS) - H1-4 (CLTS) Always Below 1 Ω
      G63-21 (CLTE) - Body ground Always 10 kΩ or higher
      G63-19 (CLTB) - Body ground Always 10 kΩ or higher
      G63-20 (CLTS) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. CHECK MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)


    1. B006O1QC18
      *a

      Component with a harness connected

      (Main Body ECU [Multiplex Network Body ECU])

      Remove the junction block assembly LH and main body ECU (multiplex network body ECU) as a unit with the connectors still connected.

      Click here

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      G63-19 (CLTB) - G63-21 (CLTE) 1 minute has elapsed without operating any switches or opening or closing the doors after turning the engine switch off Below 1 V
      Engine switch on (IG), headlight dimmer switch in AUTO 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

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

    OK

  6. CHECK AUTOMATIC LIGHT CONTROL SENSOR


    1. Check the automatic light control sensor.

      Click here

      Result
      Proceed to
      OK
      NG

    OK

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

    NG

    REPLACE AUTOMATIC LIGHT CONTROL SENSOR Click here