ENGINE IMMOBILISER SYSTEM(w/o 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 transponder key ECU is stuck on HI output, the ECM stores this DTC.

DTC Code DTC Detection Condition Trouble Area
B279A The communication line (EFIO-IMI) between the ECM and transponder key ECU is stuck on HI output for 6 seconds or more.

  • Harness or connector

  • Transponder key ECU

  • ECM

WIRING DIAGRAM

A002QPTE15

CAUTION / NOTICE / HINT

Note


  • When the transponder key ECU and/or ECM is replaced, reregister the recognition codes and ECU communication ID.

  • for 1WW:

    After turning the ignition switch off, make sure to wait at least 6 minutes before disconnecting the ECM connector or replacing the ECM.

PROCEDURE


  1. CLEAR DTC


    1. Clear the DTCs Click here.


    NEXT

  2. CHECK FOR DTC


    1. Check for DTCs Click here.

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

      Tech Tips

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


    B

    GO TO DIAGNOSTIC TROUBLE CODE CHART Click here

    A

  3. CHECK HARNESS AND CONNECTOR (TRANSPONDER KEY ECU - ECM)


    1. A002METE02
      Text in Illustration
      *1 for ZR Series Engine
      *2 for 1WW Engine
      *3

      Front view of wire harness connector

      (to Transponder Key ECU)
      *4

      Front view of wire harness connector

      (to ECM)

      Disconnect the H110 ECU connector.

    2. Disconnect the A76 ECM connector.

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

      Standard Resistance
      for ZR Series Engine
      Tester Connection Condition Specified Condition
      H110-13 (EFIO) - A76-28 (IMI) Always Below 1 Ω
      H110-13 (EFIO) or A76-28 (IMI) - Body ground Always 10 kΩ or higher
      for 1WW Engine
      Tester Connection Condition Specified Condition
      H110-13 (EFIO) - A76-34 (IMI) Always Below 1 Ω
      H110-13 (EFIO) or A76-34 (IMI) - Body ground Always 10 kΩ or higher

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

      Standard Voltage
      for ZR Series Engine
      Tester Connection Condition Specified Condition
      H110-13 (EFIO) - Body ground Always Below 1 V
      A76-28 (IMI) - Body ground
      for 1WW Engine
      Tester Connection Condition Specified Condition
      H110-13 (EFIO) - Body ground Always Below 1 V
      A76-34 (IMI) - Body ground

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK TRANSPONDER KEY ECU (OUTPUT)


    1. A002LVVE02
      *1 Component with harness connected: (Transponder Key ECU)
      *2 Normal Waveform
      *3 LOW

      Using an oscilloscope, check the waveform.

      Measurement Condition
      Item Content
      Tester Connection H110-13 (EFIO) - H110-16 (GND)
      Tool Setting 10 V/DIV., 100 msec./DIV.
      Condition Ignition switch ON
      OK
      Waveform is output normally (refer to illustration).

      Tech Tips

      If replacing the ECM, refer to the procedures below.



    OK

    REPLACE ECM

    NG

  5. CHECK TRANSPONDER KEY ECU (POWER SOURCE AND BODY GROUND)


    1. A002OE8E02
      Text in Illustration
      *1

      Component with harness connected

      (Transponder Key ECU)

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      H110-1 (+B) - H110-16 (GND) Always 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. REPLACE TRANSPONDER KEY ECU


    1. Replace the transponder key ECU.


    NEXT

  7. REGISTER ECU - ECM COMMUNICATION ID


    1. Register the ECU - ECM communication ID.


    NEXT

  8. CLEAR DTC


    1. Clear the DTCs Click here.


    NEXT

  9. CHECK FOR DTC


    1. Check for DTCs Click here.

      OK
      DTC B279A is not output.

      Tech Tips

      If replacing the ECM, refer to the procedures below.



    OK

    END (TRANSPONDER KEY ECU IS DEFECTIVE)

    NG

    REPLACE ECM