ENTRY AND START SYSTEM(for Start Function), 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*).

  • Harness or connector

  • ID code box (immobiliser code ECU)

  • ECM

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

B006C4NE02
*a ID Code Box (Immobiliser Code ECU)

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. 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 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 entry and start system (for Start Function) after confirming that the communication systems are functioning properly.

    Click here

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

  • After repair, 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. 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
      Result Proceed to
      The connectors are properly connected A
      The connectors are not properly connected B

    B

    CONNECT CONNECTORS PROPERLY

    A

  2. CHECK ECM (TERMINAL EFIO)


    1. Using an oscilloscope, check the waveform.

      B006CCOC10
      *a

      Component with harness connected

      (ID Code Box (Immobiliser Code ECU))

      		 *b Waveform
      *c Approximately 160 ms. *d Approximately 270 ms.
      Measurement Condition
      Tester Connection Condition Tool Setting Specified Condition
      G58-4 (EFIO) - Body ground Within 3 seconds of engine start or within 3 seconds of engine switch turned on (IG) after cable disconnected and reconnected to battery 2 V/DIV., 500 ms./DIV.

      Pulse generation

      (See waveform)
      Result
      Result Proceed to
      11 to 14 V A
      Below 1 V B
      Normal waveform C

    A

    REPLACE ID CODE BOX (IMMOBILISER CODE ECU)

    C

    REPLACE ECM Click here

    B

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


    1. Disconnect the A56 ECM connector.

    2. Disconnect the G58 ID code box (immobiliser code ECU) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G58-4 (EFIO) - A56-59 (IMI) Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR