ENGINE IMMOBILISER SYSTEM (w/ Smart Key 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 ECM and certification ECU (smart key ECU assembly) is stuck high, the ECM stores this DTC.

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

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

  • Certification ECU (smart key ECU assembly)

  • 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

A01HZT4E37

INSPECTION PROCEDURE

Note


  • When replacing the certification ECU (smart key ECU assembly), refer to Registration Click here.

  • After performing repairs, 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 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.

    NG

    CONNECT CONNECTORS PROPERLY

    OK

  4. CHECK WHETHER ENGINE STARTS


    1. Using an electrical key transmitter sub-assembly which is registered to the vehicle, turn the engine switch on (IG).

    2. Check that the engine starts 5 seconds after the engine switch was turned on (IG).

      OK
      Engine starts normally.
      Result
      Result Proceed to
      NG A
      OK B

    B

    USE SIMULATION METHOD TO CHECK Click here

    A

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


    1. Disconnect the A43 certification ECU (smart key ECU assembly) connector.

    2. Disconnect the A25 ECM connector.

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

      Standard Resistance
      for 2GR-FE
      Tester Connection Condition Specified Condition
      A43-13 (EFIO) - A25-31 (IMI) Always Below 1 Ω
      A43-13 (EFIO) or A25-31 (IMI) - Body ground Always 10 kΩ or higher
      for 2AR-FE
      Tester Connection Condition Specified Condition
      A43-13 (EFIO) - A25-28 (IMI) Always Below 1 Ω
      A43-13 (EFIO) or A25-28 (IMI) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)


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


    NEXT

  7. REGISTER ECU COMMUNICATION ID


    1. Register the ECU communication ID Click here.


    NEXT

  8. CLEAR DTC


    1. Clear the DTCs Click here.


    NEXT

  9. CHECK FOR DTC


    1. Perform "DTC Output Confirmation Operation" procedure.

    2. Check for DTCs Click here.

      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) WAS DEFECTIVE)