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 ECM and ID code box (immobiliser code ECU) 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 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)

  • 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

A01FIZ7E21

INSPECTION PROCEDURE

Note


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

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

Tech Tips

When DTC B279A 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 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
    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.

    NG
    OK
  4. CHECK HARNESS AND CONNECTOR (ID CODE BOX [IMMOBILISER CODE ECU] - ECM)


    1. Disconnect the N73 ID code box (immobiliser code ECU) connector.

    2. Disconnect the A21 ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      N73-4 (EFIO) - A21-31 (IMI) Always Below 1 Ω
      A21-31 (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
      A21-31 (IMI) - Body ground Always Below 1 V

    NG
    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 the Service Bulletin.


    NEXT
  6. REGISTER RECOGNITION CODES


    1. Register the recognition codes in the ECUs.

      Tech Tips

      Refer to the Service Bulletin.


    NEXT
  7. REGISTER ECU COMMUNICATION ID


    1. Register the ECU communication ID.

      Tech Tips

      Refer to the Service Bulletin.


    NEXT
  8. CLEAR DTC


    1. Clear the DTCs Click here.


    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.
      Result
      Result Proceed to
      OK A
      NG (for 2GR-FSE) B
      NG (for 4GR-FSE) C

    B
    C
    A