IMMOBILISER SYSTEM, Diagnostic DTC:B279A12

DTC Code DTC Name
B279A12 Engine Immobiliser System Circuit Short to Battery

DESCRIPTION

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

DTC No. Detection Item DTC Detection Condition Trouble Area Note
B279A12 Engine Immobiliser System Circuit Short to Battery The communication line (IMI - EFIO) between the ECM and ID code box (immobiliser code ECU) is stuck high. (1 trip detection logic*1)

  • ID code box (immobiliser code ECU)

  • ECM

  • Harness or connector

  • Telephone transceiver assembly*2

DTC output confirmation operation:


  • 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 Engine cannot be started
Related Data List and Active Test
DTC No. Data List and Active Test
B279A12 -

WIRING DIAGRAM


  1. w/o Blocking System

    B00590PE99
    *a ID Code Box (Immobiliser Code ECU)

  2. w/ Blocking System

    A01HFO6E11
    *a Telephone Transceiver Assembly
    *b ID Code Box (Immobiliser Code ECU)

CAUTION / NOTICE / HINT

Note


  • When using the GTS with the engine switch off, connect the GTS to the DLC3 and turn a courtesy light switch on and off at intervals of 1.5 seconds or less until communication between the GTS and the vehicle begins. Then select Model Code "KEY REGIST" under manual mode and enter the following menus: Body Electrical / Entry&Start(CAN). While using the GTS, periodically turn a courtesy light switch on and off at intervals of 1.5 seconds or less to maintain communication between the GTS and the vehicle.

  • Before replacing the ECM, telephone transceiver assembly* or ID code box (immobiliser code ECU), refer to Service Bulletin.

  • After repair, confirm that no DTCs are output by performing "DTC Output Confirmation Operation."

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


  • *: w/ Blocking System

Tech Tips

When DTC B279A12 and a 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.


      Powertrain > Engine > Clear DTCs
      Result
      Proceed to
      NEXT

    NEXT

  2. CHECK FOR DTC


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

    2. Check for DTCs.


      Powertrain > Engine > Trouble Codes

      Tech Tips

      If DTCs other than DTC B279A12 are output, troubleshoot those DTCs first.

      Result
      Result Proceed to
      DTC B279A12 is output A
      DTC B279A12 and other DTCs are output B

    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, telephone transceiver assembly* and ID code box (immobiliser code ECU).


      • *: w/ Blocking System

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

    B

    CHECK HARNESS AND CONNECTOR (ECM - TELEPHONE TRANSCEIVER ASSEMBLY) Click here

    C

    CONNECT CONNECTORS PROPERLY

    A

  4. CHECK HARNESS AND CONNECTOR (ID CODE BOX (IMMOBILISER CODE ECU) - ECM)


    1. Disconnect the I26 ID code box (immobiliser code ECU) connector.

    2. Disconnect the A35 ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      I26-4 (EFIO) - A35-28 (IMI) Always Below 1 Ω
      I26-4 (EFIO) or A35-28 (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
      A35-28 (IMI) - Body ground Always Below 1 V
      Result
      Proceed to
      OK
      NG

    OK

    GO TO STEP 11 Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

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


    1. Disconnect the A35 ECM connector.

    2. Disconnect the I131 telephone transceiver assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A35-28 (IMI) - I131-8 (BLK3) Always Below 1 Ω
      A35-28 (IMI) or I131-8 (BLK3) - 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
      A35-28 (IMI) - Body ground Always Below 1 V
      I131-8 (BLK3) - Body ground Always Below 1 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


    1. Disconnect the I26 ID code box (immobiliser code ECU) connector.

    2. Disconnect the I131 telephone transceiver assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      I26-4 (EFIO) - I131-2 (BLK4) Always Below 1 Ω
      I26-4 (EFIO) or I131-2 (BLK4) - 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
      I26-4 (EFIO) - Body ground Always Below 1 V
      I131-2 (BLK4) - Body ground Always Below 1 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  7. REPLACE TELEPHONE TRANSCEIVER ASSEMBLY


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

      Tech Tips

      Refer to Service Bulletin.

      Result
      Proceed to
      NEXT

    NEXT

  8. REGISTER ECU COMMUNICATION ID


    1. Register the ECU communication ID.

      Tech Tips

      Refer to Service Bulletin.

      Result
      Proceed to
      NEXT

    NEXT

  9. CLEAR DTC


    1. Clear the DTCs.


      Powertrain > Engine > Clear DTCs
      Result
      Proceed to
      NEXT

    NEXT

  10. CHECK FOR DTC


    1. Check for DTCs.


      Powertrain > Engine > Trouble Codes

      Tech Tips

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

      OK
      DTC B279A12 is not output.
      Result
      Proceed to
      OK
      NG

    OK

    END (TELEPHONE TRANSCEIVER ASSEMBLY WAS DEFECTIVE)

    NG

  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 Service Bulletin.

      Result
      Proceed to
      NEXT

    NEXT

  12. REGISTER RECOGNITION CODE


    1. Register the recognition codes in the ECUs.

      Tech Tips

      Refer to Service Bulletin.

      Result
      Proceed to
      NEXT

    NEXT

  13. REGISTER ECU COMMUNICATION ID


    1. Register the ECU communication ID.

      Tech Tips

      Refer to Service Bulletin.

      Result
      Proceed to
      NEXT

    NEXT

  14. CLEAR DTC


    1. Clear the DTCs.


      Powertrain > Engine > Clear DTCs
      Result
      Proceed to
      NEXT

    NEXT

  15. CHECK FOR DTC


    1. Perform "DTC Output Confirmation Operation" procedure.

    2. Check for DTCs.


      Powertrain > Engine > Trouble Codes
      OK
      DTC B279A12 is not output.
      Result
      Proceed to
      OK
      NG

    OK

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

    NG

    REPLACE ECM Click here