ENGINE IMMOBILISER SYSTEM, Diagnostic DTC:B279A

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

DESCRIPTION

When the communication line (IMI - EFIO) between the power management control ECU and ID code box (immobiliser code ECU) is stuck high, the power management control ECU stores this DTC.

DTC Code DTC Detection Condition Trouble Area DTC Output Confirmation Operation
B279A The communication line (IMI - EFIO) between the power management control ECU and ID code box (immobiliser code ECU) is stuck high (1 trip detection logic*1).

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

  • ID code box (immobiliser code ECU)

  • Power management control ECU

  • Telephone transceiver assembly*2

 Turn the power 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
Hybrid control system cannot be started Hybrid control system cannot be started
Related Data List and Active Test
DTC Code Data List and Active Test
B279A -

WIRING DIAGRAM


  1. w/o Blocking System

    A003X8PE24

  2. w/ Blocking System

    A003WW2E04

INSPECTION PROCEDURE

Note


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

  • The fixed 12 V power source voltage in the power management control ECU is output through a resistance from terminal IMI. The ID code box (immobiliser code ECU) grounds or does not ground this power source voltage accordingly.

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


  • *: w/ Blocking System

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 power 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 power switch off.

    2. Check that the connectors are properly connected to the power management control ECU and ID code box (immobiliser code ECU).

      OK
      Connectors are properly connected.

    NG

    CONNECT CONNECTORS PROPERLY

    OK

  4. SYSTEM CHECK


    1. Check the vehicle specification.

      Result
      Result Proceed to
      w/o Blocking System A
      w/ Blocking System B

    B

    CHECK HARNESS AND CONNECTOR (POWER MANAGEMENT CONTROL ECU - TELEPHONE TRANSCEIVER ASSEMBLY) Click here

    A

  5. CHECK HARNESS AND CONNECTOR (ID CODE BOX - POWER MANAGEMENT CONTROL ECU)


    1. Disconnect the H22 ID code box (immobiliser code ECU) connector.

    2. Disconnect the H4 power management control ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H22-6 (EFIO) - H4-21 (IMI) Always Below 1 Ω
      H4-21 (IMI) - Body ground Always 10 kΩ or higher

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      H4-21 (IMI) - Body ground Always Below 1 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. REPLACE ID CODE BOX (IMMOBILISER CODE ECU)


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


    NEXT

  7. CLEAR DTC


    1. Clear the DTCs Click here.


    NEXT

  8. REGISTER RECOGNITION CODES


    1. Register the recognition codes in the ECUs.

      Tech Tips

      Refer to the Service Bulletin.


    NEXT

  9. REGISTER ECU COMMUNICATION ID (ID CODE BOX - POWER MANAGEMENT CONTROL ECU)


    1. Register the ECU communication ID.

      Tech Tips

      Refer to the Service Bulletin.


    NEXT

  10. 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.

    NG

    REPLACE POWER MANAGEMENT CONTROL ECU Click here

    OK

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

  11. CHECK HARNESS AND CONNECTOR (POWER MANAGEMENT CONTROL ECU - TELEPHONE TRANSCEIVER ASSEMBLY)


    1. Disconnect the H149 telephone transceiver assembly connector.

    2. Disconnect the H4 power management control ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H149-8 (BLK3) - H4-21 (IMI) Always Below 1 Ω
      H4-21 (IMI) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  12. CHECK HARNESS AND CONNECTOR (ID CODE BOX (IMMOBILISER CODE ECU) - TELEPHONE TRANSCEIVER ASSEMBLY)


    1. Disconnect the H22 ID code box (immobiliser code ECU) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H149-2 (BLK4) - H22-6 (EFIO) Always Below 1 Ω
      H22-6 (EFIO) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  13. 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

  14. ECU CODE REGISTRATION


    1. Register the ECU communication ID.

      Tech Tips

      Refer to the Service Bulletin.


    NEXT

  15. CLEAR DTC


    1. Clear the DTCs Click here.


    NEXT

  16. 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 ID CODE BOX (IMMOBILISER CODE ECU) Click here

    OK

    END (TELEPHONE TRANSCEIVER ASSEMBLY WAS DEFECTIVE)

  17. 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

  18. RESISTER RECOGNITION CODES


    1. Register the key.

      Tech Tips

      Refer to the Service Bulletin.


    NEXT

  19. RESISTER ECU COMMUNICATION ID


    1. Register the ECU communication ID.

      Tech Tips

      Refer to the Service Bulletin.


    NEXT

  20. CLEAR DTC


    1. Clear the DTCs Click here.


    NEXT

  21. 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.

    NG

    REPLACE POWER MANAGEMENT CONTROL ECU Click here

    OK

    END (ID CODE BOX (IMMOBILISER CODE ECU))