ENGINE IMMOBILISER SYSTEM(w/o Entry and Start System), Diagnostic DTC:B279A

DTC Code DTC Name
B279A Theft Deterrent System Communication Line High Fixation

DESCRIPTION

When the communication line (EFIO-IMI) between the transponder key ECU assembly and ECM is stuck on HI output, the ECM stores this DTC.

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

  • Harness or connector

  • Transponder key ECU assembly

  • ECM

 Turn the ignition switch to ON 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

A005I9UE01

CAUTION / NOTICE / HINT

Note


  • When replacing the transponder key ECU assembly or ECM, refer to the Service Bulletin.

  • Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE


  1. CLEAR DTC


    1. Clear the DTCs Click here.


    NEXT

  2. CHECK FOR DTC


    1. Check for DTCs Click here.

      OK
      DTC B279A is not output.

    OK

    USE SIMULATION METHOD TO CHECK Click here

    NG

  3. CHECK HARNESS AND CONNECTOR (TRANSPONDER KEY ECU - ECM)


    1. Disconnect the F54 transponder key ECU assembly connector.

    2. Disconnect the A58*1 or A59*2 ECM connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      F54-13 (EFIO) - A58-28 (IMI)*1 Always Below 1 Ω
      F54-13 (EFIO) - A59-78 (IMI)*2 Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      F54-13 (EFIO) or A58-28 (IMI) - Body ground*1 Always 10 kΩ or higher
      F54-13 (EFIO) or A59-78 (IMI) - Body ground*2 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
      A58-28 (IMI) - Body ground*1 Always Below 1 V
      A59-78 (IMI) - Body ground*2 Always Below 1 V

      • *1: for 1NR-FE

      • *2: for 1ND-TV


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK TRANSPONDER KEY ECU ASSEMBLY (TERMINAL EFIO)


    1. A005K9VE02
      Text in Illustration
      *a

      Component with harness connected

      (Transponder Key ECU Assembly)
      *b Waveform

      Using an oscilloscope, check the waveform.

      Measurement Condition
      Item Content
      Tester Connection F54-13 (EFIO) - F54-16 (GND)
      Tool Setting 10 V/DIV., 100 ms./DIV.
      Condition Ignition switch ON

      Tech Tips


      • The waveform shown in the illustration is an example for reference only. Noise, chattering, etc. are not shown.

      • If you forget to note the waveform, etc. and need to recheck it, disconnect and reconnect the ECM connector before rechecking it.

      OK
      Waveform is output normally (refer to illustration).
      Result
      Result Proceed to
      Terminal EFIO stuck high (10 V) A
      Normal waveform (1NR-FE) B
      Normal waveform (1ND-TV) C

    B

    REPLACE ECM Click here

    C

    REPLACE ECM Click here

    A

  5. REPLACE TRANSPONDER KEY ECU ASSEMBLY


    1. Temporarily replace the transponder key ECU assembly with a new one (Refer to service Bulletin).


    NEXT

  6. REGISTER ECU - ECM COMMUNICATION ID


    1. Register the ECU - ECM communication ID (Refer to service Bulletin).


    NEXT

  7. CHECK WHETHER ENGINE STARTS


    1. Check that the engine starts with the key.

      OK
      Engine starts normally.
      Result
      Result Proceed to
      OK A
      NG (1NR-FE) B
      NG (1ND-TV) C

    A

    END (TRANSPONDER KEY ECU WAS DEFECTIVE)

    B

    REPLACE ECM Click here

    C

    REPLACE ECM Click here