ENGINE IMMOBILISER SYSTEM, Diagnostic DTC:B279A

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

DESCRIPTION

When the communication line (IMI - EFIO) between the ECM and ID code box is stuck on HI output, the ECM stores 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 ID code box is stuck on HI output (1 trip detection logic*).

  • Harness or connector (disconnection or break in wire harness is main cause)

  • ID code box

  • ECM

Turn the engine switch on (IG) and wait 6 seconds.

  • *: Only output while a malfunction is present.

Table 1. 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
Table 2. Related Data List and Active Test

DTC Code

Data List and Active Test

B279A

-

WIRING DIAGRAM

B235863E24

CAUTION / NOTICE / HINT

Note:

  • When replacing the ID code box, refer to the Service Bulletin.

  • The fixed 12 V power source voltage in the ECM is output through a resistance from terminal IMI. The ID code box grounds or does not ground this power source voltage accordingly.

  • After performing repair, perform the operation that fulfills the DTC output confirmation operation, and then confirm that no DTCs are output again.

Tip:

When DTC B279A and the certification ECU DTC are output simultaneously, first perform troubleshooting for the certification ECU DTC.

PROCEDURE

  1. CLEAR DTC

    1. Clear the DTCs.

      Click here

      Body Electrical > Entry&Start > Clear DTCs

      Result

      Result

      NEXT
    NEXT

  2. CHECK FOR DTC

    1. Turn the engine switch on (IG) and wait 10 seconds.

    2. Check for DTCs.

      Click here

      Body Electrical > Entry&Start > Trouble Codes

      Result

      Result

      Proceed to

      DTC B279A is output

      A

      DTC B279A and other DTCs are output

      B
      Tip:

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

    B

    GO TO DIAGNOSTIC TROUBLE CODE CHART

    Click here

    A

  3. 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.

      OK

      Connectors are properly connected.

      Result

      Result

      OK

      NG
    NG

    CONNECT CONNECTORS PROPERLY

    OK

  4. CHECK HARNESS AND CONNECTOR (ID CODE BOX - ECM)

    1. Disconnect the G25 box connector.

    2. Disconnect the G45*1 or G107*2 ECM connector.

      *1: for 1UR-FE

      *2: for 1GR-FE

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

      Standard Resistance

      Table 3. for 1UR-FE

      Tester Connection

      Condition

      Specified Condition

      G25-6 (EFIO) - G45-14 (IMI)

      Always

      Below 1 Ω

      G25-6 (EFIO) or G45-14 (IMI) - Body ground

      Always

      10 kΩ or higher
      Table 4. for 1GR-FE

      Tester Connection

      Condition

      Specified Condition

      G25-6 (EFIO) - G107-14 (IMI)

      Always

      Below 1 Ω

      G25-6 (EFIO) or G107-14 (IMI) - Body ground

      Always

      10 kΩ or higher

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

      Standard Voltage

      Table 5. for 1UR-FE

      Tester Connection

      Switch Condition

      Specified Condition

      G45-14 (IMI) - Body ground

      Always

      Below 1 V
      Table 6. for 1GR-FE

      Tester Connection

      Switch Condition

      Specified Condition

      G107-14 (IMI) - Body ground

      Always

      Below 1 V

    Result

    Result

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. REPLACE ID CODE BOX

    1. Replace the ID code box with a new one (Refer to the Service Bulletin).

      Result

      Result

      NEXT
    NEXT

  6. CLEAR DTC

    1. Clear the DTCs.

      Click here

      Body Electrical > Entry&Start > Clear DTCs

      Result

      Result

      NEXT
    NEXT

  7. REGISTER RECOGNITION CODES

    1. Register the recognition codes in the ECUs (Refer to the Service Bulletin).

      Result

      Result

      NEXT
    NEXT

  8. REGISTER ECU COMMUNICATION ID (ID CODE BOX - ECM)

    1. Register the ECU communication ID (Refer to the Service Bulletin).

      Result

      Result

      NEXT
    NEXT

  9. CHECK FOR DTC

    1. Check for DTCs.

      Click here

      Body Electrical > Entry&Start > Trouble Codes

      Tip:

      Before checking for DTCs, perform the "DTC Output Confirmation Operation" procedure.

      OK

      DTC B279A is not output.

      Result

      Result

      Proceed to

      OK

      A

      NG (for 1UR-FE)

      B

      NG (for 1GR-FE)

      C
    A

    END (ID CODE BOX IS DEFECTIVE)

    B

    REPLACE ECM

    Click here

    C

    REPLACE ECM

    Click here