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. DTC Detection Condition Trouble Area
B1249 Communication between double lock door control relay assembly and main body ECU (multiplex network body ECU) interrupted for 10 seconds or more, or communication wire malfunction.

  • Double lock door control relay assembly

  • Main body ECU (multiplex network body ECU)

  • Instrument panel junction block assembly

  • Wire harness or connector

  • DBL LOCK fuse

  • ECU-B fuse

WIRING DIAGRAM

A003YPNE13

INSPECTION PROCEDURE

Tech Tips

When the main body ECU (multiplex network body ECU) has been replaced with a new part, and the cable of the negative (-) auxiliary battery terminal is reconnected, the power switch will be on (IG). Also, when the auxiliary battery has been removed and installed, the condition will be the same as it was before the auxiliary battery was disconnected.

Note


  • When using the intelligent tester to troubleshoot with the power switch off:

    Connect the intelligent tester to the DLC3, and turn the courtesy switch on and off at 1.5-second intervals until communication between the intelligent tester and vehicle begins.

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

PROCEDURE


  1. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY


    1. Remove the instrument panel junction block assembly Click here.

      A003VL4E15

    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 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
      2A-27 (LIN2) - MB-16 (LIN2) Always Below 1 Ω
      2A-27 (LIN2) - Body ground Always 10 kΩ or higher
      Text in Illustration
      *a

      Component without harness connected

      (Instrument Panel Junction Block Assembly)

      		 *b

      Component without harness connected

      (Instrument Panel Junction Block Assembly)

    NG

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY Click here

    OK

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


    1. Disconnect the H140 double lock door control relay assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      2A-27 (LIN2) - H140-9 (MPX1) Always Below 1 Ω
      2A-27 (LIN2) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


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

      Standard Voltage
      Tester Connection Condition Specified Condition
      H140-1 (+B) - Body ground Power switch off 11 to 14 V
      H140-7 (CPUB) - Body ground 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
      H140-14 (GND) - Body ground Always Below 1 Ω

    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.


    NEXT

  5. CHECK DTC OUTPUT


    1. Clear the DTC Click here.

    2. Recheck for DTCs.

      OK
      DTC B1249 is not output.

    NG

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

    OK

    END (DOUBLE LOCK DOOR CONTROL RELAY ASSEMBLY WAS DEFECTIVE)