ENGINE IMMOBILISER 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 on HI output, the ECM outputs this DTC.

DTC Code DTC Detection Condition Trouble Area
B279A When the communication line (EFIO-IMI) between the ECM and the ID code box (immobiliser code ECU) is stuck on HI output.

  • Harness or connector

  • ID code box (immobiliser code ECU)

  • ECM

WIRING DIAGRAM

A01EPS7E03

INSPECTION PROCEDURE

PROCEDURE


  1. CLEAR DTC


    1. Clear the DTCs Click here.


    NEXT

  2. CHECK FOR DTC


    1. Check for DTCs Click here.

      Tech Tips

      If 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

  3. CHECK HARNESS AND CONNECTOR (ID CODE BOX - ECM)


    1. A01ER3TE14

      for LHD:


      1. Disconnect the E28 ID code box connector.

      2. Disconnect the A38 ECU connector.

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

        Standard Resistance
        Tester Connection Condition Specified Condition
        E28-6 (EFIO) - A38-40 (IMI) Always Below 1 Ω
        E28-6 (EFIO) or A38-40 (IMI) - Body ground Always 10 kΩ or higher
        Standard Voltage
        Tester Connection Condition Specified Condition
        E28-6 (EFIO) - Body ground Always Below 1 V
        A38-40 (IMI) - Body ground
    2. A01ER3TE15

      for RHD:


      1. Disconnect the E28 box connector.

      2. Disconnect the A53 ECU connector.

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

        Standard Resistance
        Tester Connection Condition Specified Condition
        E28-6 (EFIO) - A53-40 (IMI) Always Below 1 Ω
        E28-6 (EFIO) or A53-40 (IMI) - Body ground Always 10 kΩ or higher
        Standard Voltage
        Tester Connection Condition Specified Condition
        E28-6 (EFIO) - Body ground Always Below 1 V
        A53-40 (IMI) - Body ground Always Below 1 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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

    A01EOUUE01

    1. Using an oscilloscope, check the waveform.

      Measurement Condition
      Item Content
      Tester Connection E28-6 (EFIO) - E28-8 (GND)
      Tool Setting 10 V/DIV., 100 msec./DIV.
      Condition Engine switch on (IG)
      OK
      Waveform is output normally (see illustration).
      Result
      Result Proceed to
      NG A
      OK (for 1UR-FE) B
      OK (for 3UR-FE) C

    B

    REPLACE ECM Click here

    C

    REPLACE ECM Click here

    A

  5. CHECK ID CODE BOX (POWER SOURCE AND BODY GROUND)

    A01ERTJE04

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

      Standard Voltage
      Tester Connector Condition Specified Condition
      E28-1 (+B) - E28-8 (GND) Always 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE ID CODE BOX (IMMOBILISER CODE ECU)