ENGINE IMMOBILISER SYSTEM (w/ Smart Entry and Start System), Diagnostic DTC:B279A

DTC Code DTC Name
B279A Theft Deterrent System Communication Line High Fixation

DESCRIPTION

If the communication line (EFIO - IMI) to the ID code box (immobiliser code ECU) is stuck high (e. g. shorted to +B), the ECM stores this DTC.

DTC No. DTC Detection Condition Trouble Area
B279A When the communication line (EFIO - IMI) between ECM and ID code box (immobiliser code ECU) is stuck high.

  • Wire harness or connector

  • ID code box (Immobiliser code ECU)

  • ECM

WIRING DIAGRAM

A017FG6E44

INSPECTION PROCEDURE

Note

If the ID code box (immobiliser code ECU) is replaced, register the ECU code and ECU communication ID.

PROCEDURE


  1. CHECK DTC OUTPUT


    1. Clear the DTCs Click here.

    2. Recheck for DTCs Click here.

      Tech Tips

      If any DTCs other than DTC B279A are output, troubleshoot those DTCs first.

      Result
      Result Proceed to
      DTC B279A is output A
      DTC B279A and other DTCs are output B

    B

    GO TO DIAGNOSTIC TROUBLE CODE CHART Click here

    A

  2. CHECK HARNESS AND CONNECTOR (ID CODE BOX (IMMOBILISER CODE ECU) - ECM)


    1. Disconnect the ID code box (immobiliser code ECU) connector.

    2. Disconnect the ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      D28-6 (EFIO) - D55-14 (IMI) Always Below 1 Ω
      D28-6 (EFIO) - Body ground Always 10 kΩ or higher
      Standard Voltage
      Tester Connection Condition Specified Condition
      D28-6 (EFIO) - Body ground Always Below 1 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK ID CODE BOX (IMMOBILISER CODE ECU) (OUTPUT)


    1. Reconnect the ID code box (immobiliser code ECU) connector.

    2. A017EDSE08
      Text in Illustration
      *1

      Component with harness connected

      (ID Code Box (Immobiliser Code ECU))
      *2 GND
      *3 HIGH
      *4 LOW

      Reconnect the ECM connector.

    3. Using an oscilloscope, check the waveform.

      Waveform (Reference)
      Item Content
      Terminal No. (Symbol) D28-6 (EFIO) - D28-8 (GND)
      Tool Setting 10 V/DIV., 100 ms./DIV.
      Condition Engine switch on (IG)
      OK
      Waveform is output normally (see illustration).

    NG

    REPLACE ID CODE BOX (IMMOBILISER CODE ECU) Click here

    OK

    REPLACE ECM Click here

  4. REPLACE ID CODE BOX (IMMOBILISER CODE ECU)


    1. Replace the ID code box (immobiliser code ECU).


    NEXT

  5. REGISTER ECU CODE


    1. Register the ECU code.


    NEXT

  6. REGISTER ECU COMMUNICATION ID


    1. Register the ECU communication ID.


    NEXT

  7. CHECK DTC OUTPUT


    1. Clear the DTCs Click here.

    2. Recheck for DTCs Click here.

      OK
      DTC B279A is not output.

    NG

    REPLACE ECM Click here

    OK

    END (ID CODE BOX (IMMOBILISER CODE ECU) WAS DEFECTIVE)