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LIN COMMUNICATION SYSTEM, Diagnostic DTC:B1249

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DTC Code DTC Name
B1249 Double Locking ECU Communication Stop
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DESCRIPTION

DTC B1249 is stored when communication between the double lock door control relay and main body ECU (instrument panel junction block assembly) stops for more than 10 seconds.

DTC Code DTC Detection Condition Trouble Area
B1249 Communication between the double lock door control relay and main body ECU (instrument panel junction block assembly) stops for more than 10 seconds.

  • Double lock door control relay assembly

  • Main body ECU (instrument panel junction block assembly)

  • Harness or connector
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WIRING DIAGRAM

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INSPECTION PROCEDURE

Note:

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

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

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

Tip:

When communication between the double lock door control relay and main body ECU (instrument panel junction block assembly) stops, DTC B2325 is also stored.

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PROCEDURE


  1. Click here

    CLEAR DTC


    1. Clear the DTCs (Click here).


  2. Click here

    CHECK FOR DTC


    1. Check for DTCs (Click here).

      Table 1. Result:
      Result Proceed to
      DTC B1249 is output A
      DTC B1249 is not output B

  3. Click here

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


    1. Disconnect the H79 ECU connector.

    2. Disconnect the H50 relay connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H50-9 (MPX1) - H79-23 (LIN2) Always Below 1 Ω
      H50-9 (MPX1) - Body ground Always 10 kΩ or higher
      Table 2. Text in Illustration
      *1

      Front view of wire harness connector

      (to Main Body ECU)
      *2

      Front view of wire harness connector

      (to Double Lock Door Control Relay)

  4. Click here

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


    1. Disconnect the H50 relay connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H50-14 (GND) - Body ground Always Below 1 Ω
      Standard Voltage
      Tester Connection Condition Specified Condition
      H50-1 (+B) - Body ground Always 11 to 14 V
      H50-7 (CPUB) - Body ground Always 11 to 14 V
      Table 3. Text in Illustration
      *1

      Front view of wire harness connector

      (to Double Lock Door Control Relay)

  5. Click here

    REPLACE DOUBLE LOCK DOOR CONTROL RELAY ASSEMBLY


    1. Temporarily replace the double lock door control relay with a new or normally functioning one (Click here).

    2. Clear the DTCs (Click here).


  6. Click here

    CHECK FOR DTC


    1. Check for DTCs (Click here).

      Table 4. Result
      Result Proceed to
      DTC B1249 is not output A
      DTC B1249 is output B

  7. Click here

    REPLACE MAIN BODY ECU (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

  8. Click here

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  9. Click here

    USE SIMULATION METHOD TO CHECKClick here

  10. Click here

    END (DOUBLE LOCK DOOR CONTROL RELAY IS DEFECTIVE)