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

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

DTC Code

DTC Detection Condition

Trouble Area

B279A

The communication line (EFIO-IMI) between the ECM and transponder key ECU is stuck on HI output for 6 seconds or more.

  • Harness or connector

  • Transponder key ECU

  • ECM

WIRING DIAGRAM

B225301E15

CAUTION / NOTICE / HINT

Note:

  • When the transponder key ECU and/or ECM is replaced, reregister the recognition codes and ECU communication ID.

  • for 1WW:

    After turning the ignition switch off, make sure to wait at least 6 minutes before disconnecting the ECM connector or replacing the ECM.

PROCEDURE

  1. CLEAR DTC

    1. Clear the DTCs (Click here).

  2. CHECK FOR DTC

    1. Check for DTCs (Click here).

      Table 1. Result

      Result

      Proceed to

      DTC B279A is output

      A

      DTC B279A and other DTCs are output

      B
      Tip:

      If any DTCs other than B279A are output, troubleshoot those DTCs first.

    GO TO DIAGNOSTIC TROUBLE CODE CHART

    (Click here)

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

    1. U184681E02

      Disconnect the H110 ECU connector.

    2. Disconnect the A76 ECM connector.

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

      Standard Resistance

      for ZR Series Engine

      Tester Connection

      Condition

      Specified Condition

      H110-13 (EFIO) - A76-28 (IMI)

      Always

      Below 1 Ω

      H110-13 (EFIO) or A76-28 (IMI) - Body ground

      Always

      10 kΩ or higher

      for 1WW Engine

      Tester Connection

      Condition

      Specified Condition

      H110-13 (EFIO) - A76-34 (IMI)

      Always

      Below 1 Ω

      H110-13 (EFIO) or A76-34 (IMI) - Body ground

      Always

      10 kΩ or higher

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

      Standard Voltage

      for ZR Series Engine

      Tester Connection

      Condition

      Specified Condition

      H110-13 (EFIO) - Body ground

      Always

      Below 1 V

      A76-28 (IMI) - Body ground

      for 1WW Engine

      Tester Connection

      Condition

      Specified Condition

      H110-13 (EFIO) - Body ground

      Always

      Below 1 V

      A76-34 (IMI) - Body ground
    Table 2. Text in Illustration

    *1

    for ZR Series Engine

    *2

    for 1WW Engine

    *3

    Front view of wire harness connector

    (to Transponder Key ECU)

    *4

    Front view of wire harness connector

    (to ECM)

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  4. CHECK TRANSPONDER KEY ECU (OUTPUT)

    1. U122381E02

      Using an oscilloscope, check the waveform.

      Table 3. Measurement Condition

      Item

      Content

      Tester Connection

      H110-13 (EFIO) - H110-16 (GND)

      Tool Setting

      10 V/DIV., 100 msec./DIV.

      Condition

      Ignition switch ON

      OK

      Waveform is output normally (refer to illustration).

      Tip:

      If replacing the ECM, refer to the procedures below.

    REPLACE ECM

  5. CHECK TRANSPONDER KEY ECU (POWER SOURCE AND BODY GROUND)

    1. U123841E02

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

      Standard Voltage

      Tester Connection

      Condition

      Specified Condition

      H110-1 (+B) - H110-16 (GND)

      Always

      11 to 14 V
      Table 4. Text in Illustration

      *1

      Component with harness connected

      (Transponder Key ECU)

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  6. REPLACE TRANSPONDER KEY ECU

    1. Replace the transponder key ECU.

  7. REGISTER ECU - ECM COMMUNICATION ID

    1. Register the ECU - ECM communication ID.

  8. CLEAR DTC

    1. Clear the DTCs (Click here).

  9. CHECK FOR DTC

    1. Check for DTCs (Click here).

    OK

    DTC B279A is not output.

    Tip:

    If replacing the ECM, refer to the procedures below.

    END (TRANSPONDER KEY ECU IS DEFECTIVE)

    REPLACE ECM