ENTRY AND START SYSTEM(for Start Function), Diagnostic DTC:B279986

DTC Code DTC Name
B279986 Engine Immobiliser System Signal (Some Circuit Quantity, Reported via Serial Data) Invalid

DESCRIPTION

If there is a communication malfunction between the ECM and ID code box (immobiliser code ECU), or when the communication ID codes do not match, the ECM stores this DTC.

DTC No. Detection Item DTC Detection Condition Trouble Area Note
B279986 Engine Immobiliser System Signal (Some Circuit Quantity, Reported via Serial Data) Invalid

Either of the following conditions is met (1 trip detection logic*):


  • A malfunction is detected in the communication or communication lines between the ECM and ID code box (immobiliser code ECU).

  • The communication ID codes of the ECM and ID code box (immobiliser code ECU) do not match.

  • ID code box (immobiliser code ECU)

  • ECM

  • Harness or connector

DTC output confirmation operation (Perform either of the following):


  • Start the engine and wait for 10 seconds. If there is a malfunction, the engine will stop (communication begins within 3 seconds of the engine start, and DTCs are stored after 6 seconds).

  • Connect the cable to the negative (-) battery terminal, start the engine and wait for 10 seconds (communication begins within 3 seconds of the engine switch being turned on (IG), and DTCs are stored after 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 -
Related Data List and Active Test
DTC No. Data List and Active Test
B279986 -

WIRING DIAGRAM

B000U3UE32
*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 B279986 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. REGISTER ECU COMMUNICATION ID (ID CODE BOX (IMMOBILISER CODE ECU) - ECM)


    1. Register the communication ID codes.

      Tech Tips

      Refer to Service Bulletin.

      Result
      Proceed to
      NEXT

    NEXT

  2. CHECK ECM (TERMINAL EFII)


    1. Using an oscilloscope, check the waveform.

      B000Z42C02
      *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
      P51-3 (EFII) - 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
      Normal waveform A
      Terminal IMO stuck low (2.4 V or less) B
      Waveform length or shape is abnormal, or IMO terminal stuck at Hi (12 V) C

    B

    CHECK ECM (TERMINAL IMO) Click here

    C

    CHECK HARNESS AND CONNECTOR (ID CODE BOX (IMMOBILISER CODE ECU) - ECM) Click here

    A

  3. CHECK ID CODE BOX (IMMOBILISER CODE ECU) (TERMINAL EFIO)


    1. Using an oscilloscope, check the waveform.

      B000V5WC06
      *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
      P51-4 (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
      Proceed to
      OK
      NG

    NG

    REPLACE ID CODE BOX (IMMOBILISER CODE ECU)

    OK

  4. REGISTER ECU COMMUNICATION ID (ID CODE BOX (IMMOBILISER CODE ECU) - ECM)


    1. Register the ECU communication ID codes.

      Tech Tips

      Refer to Service Bulletin.

      Result
      Proceed to
      NEXT

    NEXT

  5. CHECK WHETHER ENGINE STARTS


    1. Check that the engine starts.

      Result
      Result Proceed to
      Engine was started A
      Engine was not started B

    A

    END (ECU COMMUNICATION ID HAS NOT BEEN REGISTERED)

    B

    REPLACE ECM Click here

  6. CHECK ECM (TERMINAL IMO)


    1. B000V8DC11
      *a

      Front view of wire harness connector

      (to ECM)

      Disconnect the ECM connector.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A58-45 (IMO) - Body ground Engine switch turned on (IG) using registered electrical key transmitter sub-assembly Terminal IMO stuck low (2.4 V or less)
      Terminal IMO stuck high (12 V) or abnormal waveform
      Result
      Result Proceed to
      Terminal IMO stuck low (2.4 V or less) A
      Terminal IMO stuck high (12 V) or abnormal waveform B

    B

    REPLACE ECM Click here

    A

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


    1. Disconnect the P51 ID code box (immobiliser code ECU) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      P51-3 (EFII) - A58-45 (IMO) Always Below 1 Ω
      P51-3 (EFII) or A58-45 (IMO) - Other terminals and body ground Always 10 kΩ or higher
      P51-4 (EFIO) - A58-59 (IMI) Always Below 1 Ω
      P51-4 (EFIO) or A58-59 (IMI) - Other terminals and body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ID CODE BOX (IMMOBILISER CODE ECU)

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

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


    1. Disconnect the P51 ID code box (immobiliser code ECU) connector.

    2. Disconnect the A58 ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      P51-3 (EFII) - A58-45 (IMO) Always Below 1 Ω
      P51-3 (EFII) or A58-45 (IMO) - Other terminals and body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR