ENGINE IMMOBILISER SYSTEM (w/o 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 transponder key ECU assembly is stuck high (e.g. shorted to +B), the ECM stores this DTC.

DTC No. DTC Detection Condition Trouble Area
B279A Communication line (EFIO-IMI) between the ECM and transponder key ECU assembly is stuck high.

  • Wire harness or connector

  • ECM

  • Transponder key ECU assembly

WIRING DIAGRAM


  1. for 2AR-FE

    A01EU20E51

  2. for 1AZ-FE

    A01EU20E73

INSPECTION PROCEDURE

Note

If the transponder key ECU assembly or ECM is replaced, refer to Service Bulletin.

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 (TRANSPONDER KEY ECU - ECM)


    1. Disconnect the transponder key ECU assembly connector.

    2. Disconnect the ECM connector.

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

      Standard Resistance
      for 2AR-FE
      Tester Connection Condition Specified Condition
      I19-13 (EFIO) - A25-28 (IMI) Always Below 1 Ω
      I19-13 (EFIO) - Body ground Always 10 kΩ or higher
      for 1AZ-FE
      Tester Connection Condition Specified Condition
      I19-13 (EFIO) - A74-11 (IMI) Always Below 1 Ω
      I19-13 (EFIO) - Body ground Always 10 kΩ or higher
      Standard Voltage
      for 2AR-FE
      Tester Connection Condition Specified Condition
      I19-13 (EFIO) - Body ground Always Below 1 V
      for 1AZ-FE
      Tester Connection Condition Specified Condition
      I19-13 (EFIO) - Body ground Always Below 1 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK TRANSPONDER KEY ECU ASSEMBLY (OUTPUT)


    1. Reconnect the transponder key ECU assembly connector.

    2. Reconnect the ECM connector.

    3. Using an oscilloscope, check the waveform.

      A01EVJRE01
      Waveform (Reference)
      Item Content
      Terminal No. (Symbol) I19-13 (EFIO) - I19-16 (GND)
      Tool Setting 2 V/DIV., 500 ms/DIV.
      Condition Within 3 seconds of engine start or within 3 seconds of ignition switch turned ON after battery cable disconnected and reconnected
      OK
      Waveform is output normally (see illustration).
      Text in Illustration
      *a

      Component with harness connected

      (Transponder Key ECU Assembly)

      		 *b GND
      *c Waveform *d High
      *e Low - -

    NG

    REPLACE TRANSPONDER KEY ECU ASSEMBLY Click here

    OK

    REPLACE ECM Click here

  4. REPLACE TRANSPONDER KEY ECU ASSEMBLY


    1. Replace the transponder key ECU assembly.

      Tech Tips

      Refer to Service Bulletin.


    NEXT

  5. REGISTER KEY


    1. Register the key.

      Tech Tips

      Refer to Service Bulletin.


    NEXT

  6. REGISTER ECU COMMUNICATION ID


    1. Register the ECU communication ID.

      Tech Tips

      Refer to Service Bulletin.


    NEXT

  7. CHECK DTC OUTPUT


    1. Clear the DTCs Click here.

    2. Recheck for DTCs Click here.

      Result
      Result Proceed to
      DTC B279A is not output A
      DTC B279A is output (for 2AR-FE) B
      DTC B279A is output (for 1AZ-FE) C

    B

    REPLACE ECM Click here

    C

    REPLACE ECM Click here

    A

    END (TRANSPONDER KEY ECU ASSEMBLY WAS DEFECTIVE)