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


DTC Code DTC Detection Condition Trouble Area DTC Output Confirmation Operation
B279A The communication line (IMI - EFIO) between the ECM and ID code box (immobiliser code ECU)*1 or certification ECU (smart key ECU assembly)*2 is stuck high (1 trip detection logic*3).

  • Wire harness or connector (disconnection or break in wire harness is main cause)

  • ID code box (immobiliser code ECU)*1

  • Certification ECU (smart key ECU assembly)*2

  • Telephone transceiver assembly*4

  • ECM

 Turn the engine switch on (IG) and wait 6 seconds.

Vehicle Condition and Fail-safe Operation when Malfunction Detected
Vehicle Condition when Malfunction Detected Fail-safe Operation when Malfunction Detected
Engine cannot be started (initial ignition occurs and engine cranks, then ignition stops) Engine cannot be started
Related Data List and Active Test
DTC Code Data List and Active Test
B279A -

WIRING DIAGRAM


  1. w/o Blocking System

    A01EYGCE01

  2. w/ Blocking System

    A01EVQBE01

INSPECTION PROCEDURE

Note


  • When replacing the certification ECU (smart key ECU assembly), ID code box (immobiliser code ECU) or telephone transceiver assembly*, refer to the Service Bulletin.

  • After performing repairs, perform the operation that fulfills the DTC output confirmation operation, and then confirm that no DTCs are output again.

  • When the telephone transceiver is replaced, it is necessary to set the contract mode.*


Tech Tips

When DTC B279A and the certification ECU (smart key ECU assembly) DTC are output simultaneously, first perform troubleshooting for the certification ECU (smart key ECU assembly) DTC.

PROCEDURE


  1. CLEAR DTC


    1. Clear the DTCs Click here.


    NEXT

  2. CHECK FOR DTC


    1. Turn the engine switch on (IG) and wait 10 seconds.

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


    B

    GO TO DIAGNOSTIC TROUBLE CODE CHART Click here

    A

  3. CHECK CONNECTION OF CONNECTOR


    1. Turn the engine switch off.

    2. Check that the connectors are properly connected to the ECM and certification ECU (smart key ECU assembly).

      OK
      Connectors are properly connected.
      Result
      Result Proceed to
      OK (w/ Blocking System) A
      OK (w/o Blocking System) B
      NG C

    B

    CHECK HARNESS AND CONNECTOR (ID CODE BOX (IMMOBILISER CODE ECU)*3 OR CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)*4 - ECM) Click here

    C

    CONNECT CONNECTORS PROPERLY

    A

  4. CHECK HARNESS AND CONNECTOR (ECM - TELEPHONE TRANSCEIVER ASSEMBLY)


    1. Disconnect the I70 ECU connector.

    2. Disconnect the A25 ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      I70-8 (BLK3) - A25-31 (IMI) Always Below 1 Ω
      A25-31 (IMI) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - TELEPHONE TRANSCEIVER ASSEMBLY)


    1. Disconnect the A43 ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      I70-2 (BLK4) - A43-13 (EFIO) Always Below 1 Ω
      A43-13 (EFIO) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. REPLACE TELEPHONE TRANSCEIVER ASSEMBLY


    1. Temporarily replace the telephone transceiver assembly with a new or known good one.

      Tech Tips

      Refer to the Service Bulletin.


    NEXT

  7. REGISTER ECU COMMUNICATION ID


    1. Register the ECU communication ID.

      Tech Tips

      Refer to the Service Bulletin.


    NEXT

  8. CLEAR DTC


    1. Clear the DTCs Click here.


    NEXT

  9. CHECK DTC OUTPUT


    1. Check for DTCs Click here.

      Tech Tips

      Before checking for DTCs, perform the "DTC Output Confirmation Operation" procedure.

      OK
      DTC B279A is not output.

    NG

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) Click here

    OK

    END (TELEPHONE TRANSCEIVER ASSEMBLY WAS DEFECTIVE)

  10. CHECK HARNESS AND CONNECTOR (ID CODE BOX (IMMOBILISER CODE ECU)*3 OR CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)*4 - ECM)


    1. Disconnect the A25 ECM connector.

    2. Disconnect the I20*3 or A43*4 ECU connector.


      • *3: w/o Wireless Door Lock Buzzer Answer Back Function

      • *4: w/ Wireless Door Lock Buzzer Answer Back Function

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

      Standard Resistance
      for 2GR-FE
      Tester Connection Condition Specified Condition

      I20-4 (EFIO) - A25-31 (IMI)*3

      A43-13 (EFIO) - A25-31 (IMI)*4

      		 Always Below 1 Ω
      A25-31 (IMI) - Body ground Always 10 kΩ or higher
      for 2AR-FE
      Tester Connection Condition Specified Condition

      I20-4 (EFIO) - A25-28 (IMI)*3

      A43-13 (EFIO) - A25-28 (IMI)*4

      		 Always Below 1 Ω
      A25-28 (IMI) - Body ground Always 10 kΩ or higher

      • *3: w/o Wireless Door Lock Buzzer Answer Back Function

      • *4: w/ Wireless Door Lock Buzzer Answer Back Function

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

      Standard Voltage
      for 2GR-FE
      Tester Connection Condition Specified Condition
      A25-31 (IMI) - Body ground Always Below 1 V
      for 2AR-FE
      Tester Connection Condition Specified Condition
      A25-28 (IMI) - Body ground Always Below 1 V
      Result
      Result Proceed to
      OK (w/o Wireless Door Lock Buzzer Answer Back Function) A
      OK (w/ Wireless Door Lock Buzzer Answer Back Function) B
      NG C

    B

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) Click here

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    A

  11. REPLACE ID CODE BOX (IMMOBILISER CODE ECU)


    1. Replace the ID code box (immobiliser code ECU) with a new one.

      Tech Tips

      Refer to the Service Bulletin.


    NEXT

  12. REGISTER RECOGNITION CODES


    1. Register the recognition codes in the ECUs.

      Tech Tips

      Refer to the Service Bulletin.


    NEXT

  13. REGISTER ECU COMMUNICATION ID


    1. Register the ECU communication ID.

      Tech Tips

      Refer to the Service Bulletin.


    NEXT

  14. CLEAR DTC


    1. Clear the DTCs Click here.


    NEXT

  15. CHECK DTC OUTPUT


    1. Check for DTCs Click here.

      Tech Tips

      Before checking for DTCs, perform the "DTC Output Confirmation Operation" procedure.

      OK
      DTC B279A is not output.
      Result
      Result Proceed to
      OK A
      NG (for 2GR-FE) B
      NG (for 2AR-FE) C

    B

    REPLACE ECM Click here

    C

    REPLACE ECM Click here

    A

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

  16. REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)


    1. Replace the certification ECU (smart key ECU assembly) with a new one.

      Tech Tips

      Refer to the Service Bulletin.


    NEXT

  17. REGISTER RECOGNITION CODES


    1. Register the key.

      Tech Tips

      Refer to the Service Bulletin.


    NEXT

  18. REGISTER ECU COMMUNICATION ID


    1. Register the ECU communication ID.

      Tech Tips

      Refer to the Service Bulletin.


    NEXT

  19. CLEAR DTC


    1. Clear the DTCs Click here.


    NEXT

  20. CHECK FOR DTC


    1. Check for DTCs Click here.

      Tech Tips

      Before checking for DTCs, perform the "DTC Output Confirmation Operation" procedure.

      OK
      DTC B279A is not output.
      Result
      Result Proceed to
      OK A
      NG (for 2GR-FE) B
      NG (for 2AR-FE) C

    B

    REPLACE ECM Click here

    C

    REPLACE ECM Click here

    A

    END (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY))