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*).

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

  • ID code box (immobiliser code ECU)

  • Power management control ECU

 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

A003X8PE20

INSPECTION PROCEDURE

Note


  • When replacing the ID code box (immobiliser code ECU), refer to the Service Bulletin.

  • 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.

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


    1. Disconnect the H22 box connector.

    2. Disconnect the H4 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

  5. REPLACE ID CODE BOX (IMMOBILISER CODE ECU)


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


    NEXT

  6. CLEAR DTC


    1. Clear the DTCs Click here.


    NEXT

  7. REGISTER RECOGNITION CODES


    1. Register the recognition codes in the ECUs.


    NEXT

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


    1. Register the ECU communication ID.


    NEXT

  9. 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)