ENGINE IMMOBILISER SYSTEM, Diagnostic DTC:B279A

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

DESCRIPTION

If the communication line (EFIO - IMI) to the transponder key ECU is stuck on HI output, the ECM stores this DTC.

DTC No. DTC Detection Condition Trouble Area
B279A The communication line (EFIO - IMI) between the ECM and the transponder key ECU is stuck on HI output.

  • ECM

  • Transponder key ECU

  • Wire harness

WIRING DIAGRAM

A01BG9AE01

INSPECTION PROCEDURE

Note

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

PROCEDURE


  1. CLEAR DTC


    1. Clear the DTCs.


    NEXT

  2. CHECK FOR DTC


    1. Check for DTCs.

      Result
      Result Proceed to
      DTC B279A is output A
      DTC B279A and other DTCs are output B

    B

    GO TO DIAGNOSTIC TROUBLE CODE CHART

    A

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


    1. A01BEY6E02

      Disconnect the H44 transponder key ECU connector.

    2. Disconnect the B7*1 or B47*2 ECM connector.


      • *1: 2TR-FE

      • *2: 1KD-FTV

    3. Measure the resistance of the wire harness side connectors.

      Standard resistance (Check for open)
      2TR-FE
      Tester Connection Specified Condition
      H44-13 (EFIO) - B7-16 (IMI) Below 1 Ω
      1KD-FTV
      Tester Connection Specified Condition
      H44-13 (EFIO) - B47-28 (IMI) Below 1 Ω
      Standard resistance (Check for short)
      2TR-FE
      Tester Connection Specified Condition
      H44-13 (EFIO) or B7-16 (IMI) - Body ground 10 kΩ or higher
      1KD-FTV
      Tester Connection Specified Condition
      H44-13 (EFIO) or B47-28 (IMI) - Body ground 10 kΩ or higher

    4. Reconnect the ECM connector.

    5. Reconnect the transponder key ECU connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK ECM (INPUT)


    1. A01BETEE02

      Using an oscilloscope, check the waveform.

      2TR-FE
      Tester Connection Tool Setting Condition Specified Condition
      B7-16 (IMI) - Body ground 10 V/DIV., 100 ms./DIV. Ignition switch ON See waveform
      1KD-FTV
      Tester Connection Tool Setting Condition Specified Condition
      B47-28 (IMI) - Body ground 10 V/DIV., 100 ms./DIV. Ignition switch ON See waveform
      OK
      Waveform is output normally (refer to illustration).

    NG

    CHECK HARNESS AND CONNECTOR (TRANSPONDER KEY ECU - BATTERY AND BODY GROUND) Click here

    OK

    REPLACE ECM

  5. CHECK HARNESS AND CONNECTOR (TRANSPONDER KEY ECU - BATTERY AND BODY GROUND)


    1. A01BI4OE08

      Disconnect the H44 transponder key ECU connector.

    2. Measure the voltage of the wire harness side connectors.

      Standard voltage
      Tester Connection Specified Condition
      H44-1 (+B) - Body ground 11 to 14 V

    3. Measure the resistance of the wire harness side connectors.

      Standard resistance
      Tester Connection Specified Condition
      H44-16 (GND) - Body ground Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. REPLACE TRANSPONDER KEY ECU


    1. Temporarily replace the transponder key ECU with a new one.


    NEXT

  7. REGISTER ECU COMMUNICATION ID


    1. Register the ECU communication ID.


    NEXT

  8. CLEAR DTC


    1. Clear the DTCs.


    NEXT

  9. CHECK FOR DTC


    1. Check for DTCs.

      OK
      DTC B279A is not output.

    NG

    REPLACE ECM

    OK

    END (TRANSPONDER KEY ECU IS DEFECTIVE)