SMART ENTRY AND START SYSTEM(for Start Function), Diagnostic DTC:B279A, B279A12

DTC Code DTC Name
B279A Theft Deterrent System Communication Line High Fixation
B279A12 Engine Immobiliser System Circuit Short to Battery

DESCRIPTION

If the communication line (IMI - EFIO) between the ECM and certification ECU (smart key ECU assembly) is stuck high, the ECM will store this DTC.

DTC No. Detection Item DTC Detection Condition Trouble Area Note
B279A Theft Deterrent System Communication Line High Fixation The communication line (IMI - EFIO) between the ECM and certification ECU (smart key ECU assembly) is stuck high. (1 trip detection logic*)

  • Certification ECU (smart key ECU assembly)

  • ECM

  • Wire harness or connector

DTC output confirmation operation:


  • Turn the engine switch on (IG) and wait 6 seconds.
B279A12 Engine Immobiliser System Circuit Short to Battery The communication line (IMI - EFIO) between the ECM and certification ECU (smart key ECU assembly) is stuck high. (1 trip detection logic*)

  • Certification ECU (smart key ECU assembly)

  • 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

B279A*1

B279A12*2

 -

WIRING DIAGRAM

B006XXJE08

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.

  • The smart entry and start system (for Start Function) uses the LIN communication system and CAN communication system. Inspect the communication function by following How to Proceed with Troubleshooting. Troubleshoot the smart entry and start system (for Start Function) after confirming that the communication systems are functioning properly.

    Click here

  • Before replacing the ECM or certification ECU (smart key ECU assembly), 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 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. 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.
      Result
      Proceed to
      OK
      NG

    NG

    CONNECT CONNECTORS PROPERLY

    OK

  2. CHECK WHETHER ENGINE STARTS


    1. Check that the engine starts.

      OK
      Engine starts normally.
      Result
      Proceed to
      OK
      NG

    OK

    USE SIMULATION METHOD TO CHECK Click here

    NG

  3. CHECK ECM


    1. B0070KWC25
      *a

      Component with harness connected

      (Certification ECU (Smart Key ECU Assembly))

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A13-4 (EFIO) - Body ground Engine switch on (IG) 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - ECM) Click here

    OK

  4. CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) (TERMINAL EFIO)


    1. Using an oscilloscope, check the waveform.

      B0071TZC02
      *a

      Component with harness connected

      (Certification ECU (Smart Key ECU Assembly))

      		 *b Waveform
      *c Approximately 160 ms. *d Approximately 270 ms.
      OK
      Tester Connection Condition Tool Setting Specified Condition
      A13-4 (EFIO) - Body ground Engine switch turned on (IG) using registered electrical key transmitter sub-assembly 2 V/DIV., 500 ms./DIV.

      Pulse generation

      (See waveform)
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ECM for A25A-FKS: Click here
    REPLACE ECM for 2GR-FKS: Click here
    REPLACE ECM for 2AR-FE: Click here

    NG

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

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


    1. Disconnect the A24*1, A23*2 or A22*3 ECM connector.


      • *1: for A25A-FKS

      • *2: for 2GR-FKS

      • *3: for 2AR-FE

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

      Standard Resistance
      for A25A-FKS
      Tester Connection Condition Specified Condition
      A13-4 (EFIO) - A24-26 (IMI) Always Below 1 Ω
      for 2GR-FKS
      Tester Connection Condition Specified Condition
      A13-4 (EFIO) - A23-59 (IMI) Always Below 1 Ω
      for 2AR-FE
      Tester Connection Condition Specified Condition
      A13-4 (EFIO) - A22-28 (IMI) Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ECM for A25A-FKS: Click here
    REPLACE ECM for 2GR-FKS: Click here
    REPLACE ECM for 2AR-FE: Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR