IMMOBILISER SYSTEM, Diagnostic DTC:B279A12

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

DESCRIPTION

If the communication line (IMI - EFIO) between the ECM and ID code box (immobiliser code ECU) is stuck high, the ECM will store 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*)

  • ID code box (immobiliser code ECU)

  • ECM

  • Wire harness or connector

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

A01VU8TE05

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 the vehicle type 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 or ID code box (immobiliser code ECU), refer to Service Bulletin.

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

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
      Only 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 and ID code box (immobiliser code ECU).

      OK
      Connectors are properly connected.
      Result
      Proceed to
      OK
      NG

    NG

    CONNECT CONNECTORS PROPERLY

    OK

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


    1. Disconnect the J36 ID code box (immobiliser code ECU) connector.

    2. Disconnect the A46*1 or A37*2 ECM connector.


      • *1: for 8AR-FTS

      • *2: for 2GR-FKS

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

      Standard Resistance
      for 8AR-FTS
      Tester Connection Condition Specified Condition
      J36-4 (EFIO) - A46-28 (IMI) Always Below 1 Ω
      J36-4 (EFIO) or A46-28 (IMI) - Body ground Always 10 kΩ or higher
      for 2GR-FKS
      Tester Connection Condition Specified Condition
      J36-4 (EFIO) - A37-59 (IMI) Always Below 1 Ω
      J36-4 (EFIO) or A37-59 (IMI) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    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.

      Tech Tips

      Refer to Service Bulletin.

      Result
      Proceed to
      NEXT

    NEXT

  6. REGISTER RECOGNITION CODE


    1. Register the recognition codes in the ECUs.

      Tech Tips

      Refer to Service Bulletin.

      Result
      Proceed to
      NEXT

    NEXT

  7. REGISTER ECU COMMUNICATION ID


    1. Register the ECU communication ID.

      Tech Tips

      Refer to Service Bulletin.

      Result
      Proceed to
      NEXT

    NEXT

  8. CHECK WHETHER ENGINE STARTS


    1. Check that the engine starts.

      OK
      Engine starts normally.
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE ECM for 8AR-FTS: Click here
    REPLACE ECM for 2GR-FKS: Click here

    OK

  9. CLEAR DTC


    1. Clear the DTCs.


      Powertrain > Engine > Clear DTCs
      Result
      Proceed to
      NEXT

    NEXT

  10. 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 ID CODE BOX (IMMOBILISER CODE ECU)