LIN COMMUNICATION SYSTEM, Diagnostic DTC:B1249

DTC Code DTC Name
B1249 Double Locking ECU Communication Stop

DESCRIPTION

The main body ECU (multiplex network body ECU) stores this DTC when communication with the double lock door control relay assembly is interrupted for 10 seconds or more.

DTC No. Detection Item DTC Detection Condition Trouble Area
B1249 Double Locking ECU Communication Stop No communication between double lock door control relay assembly and main body ECU (multiplex network body ECU) for 10 seconds or more

  • Double lock door control relay assembly

  • Main body ECU (multiplex network body ECU)

  • Instrument panel junction block assembly

  • Wire harness or connector

  • DOOR DBL/L fuse

  • MPX-B NO. 1 fuse

WIRING DIAGRAM

A01MRSUE22

CAUTION / NOTICE / HINT

Note


  • Inspect the fuses for circuits related to this system before performing the following procedure.

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

PROCEDURE


  1. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY


    1. Remove the instrument panel junction block assembly.

      Click here

      A01MS2NC05
      *a

      Component without harness connected

      (Instrument Panel Junction Block Assembly)

      		 - -

    2. Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly.

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

      Tech Tips

      This inspection is to check the LIN communication line in the instrument panel junction block assembly that connects the wire harness to the built-in main body ECU (multiplex network body ECU).

      Standard Resistance
      Tester Connection Condition Specified Condition
      4B-21 - MB-16 (LIN2) Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY Click here

    OK

  2. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) - DOUBLE LOCK DOOR CONTROL RELAY ASSEMBLY)


    1. Disconnect the K138 double lock door control relay assembly connector.

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

      Note

      Make sure that each ECU is in sleep mode before performing the inspection. To enter sleep mode, turn the power switch from on (IG) to off and wait for 60 seconds or more without operating any switches.

      Standard Resistance
      Tester Connection Condition Specified Condition
      4B-21 - K138-9 (LIN) Power switch off Below 1 Ω
      K138-9 (LIN) - Body ground Power switch off 10 kΩ or higher
      4B-21 - Body ground Power switch off 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK HARNESS AND CONNECTOR (DOUBLE LOCK DOOR CONTROL RELAY ASSEMBLY - AUXILIARY BATTERY, BODY GROUND)


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

      Standard Voltage
      Tester Connection Condition Specified Condition
      K138-12 (+B) - K138-7 (GND) Power switch off 11 to 14 V
      K138-11 (CPUB) - K138-7 (GND) Power switch off 11 to 14 V

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      K138-7 (GND) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. REPLACE DOUBLE LOCK DOOR CONTROL RELAY ASSEMBLY


    1. Replace the double lock door control relay assembly.

      Click here

      Result
      Proceed to
      NEXT

    NEXT

  5. CHECK DTC OUTPUT


    1. Clear the DTCs.

      Click here


      Body Electrical > Main Body > Clear DTCs

    2. Recheck for DTCs.


      Body Electrical > Main Body > Trouble Codes
      OK
      DTC B1249 is not output.
      Result
      Proceed to
      OK
      NG

    OK

    END (DOUBLE LOCK DOOR CONTROL RELAY ASSEMBLY WAS DEFECTIVE)

    NG

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