ENGINE IMMOBILISER SYSTEM, Diagnostic DTC:B2796, B2798

DTC Code DTC Name
B2796 No Communication in Immobiliser System
B2798 Communication Malfunction No. 2

DESCRIPTION

When a key is inserted into the ignition key cylinder but no communication occurs between the key and transponder key ECU, DTC B2796 is output. When a key is inserted into the ignition key cylinder but a communication error occurs between the key and transponder key ECU, DTC B2798 is output.

DTC No. DTC Detection Condition Trouble Area
B2796 No communication

  • Key

  • Transponder key amplifier

  • Wire harness

  • Transponder key ECU
B2798 Communication error Key

WIRING DIAGRAM

A01BAZ5E39

INSPECTION PROCEDURE

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER (ENGINE IMMOBILISER SYSTEM)


    1. Check the Data List for proper functioning of the engine immobiliser system.

      Transponder key ECU:
      Item Measurement Item / Display (Range) Normal Condition Diagnostic Note
      Immobiliser Immobiliser system status / SET or UNSET

      UNSET: Ignition switch ON

      SET: No key is in ignition key cylinder

      		 -
      OK
      UNSET (ignition switch ON) appears on screen.

    OK

    REPLACE TRANSPONDER KEY ECU

    NG

  2. CHECK WHETHER ENGINE STARTS WITH OTHER KEY


    1. Check whether the engine starts with the vehicle's other keys.

      OK
      Engine starts.

    OK

    REREGISTER OR REPLACE KEY THAT CANNOT START ENGINE

    NG

  3. READ VALUE USING INTELLIGENT TESTER (TRANSPONDER KEY COIL)


    1. Check the Data List for proper functioning of the transponder key coil.

      Transponder key ECU assembly:
      Item Measurement Item / Display (Range) Normal Condition Diagnostic Note
      Antenna Coil Status Transponder key coil condition / NORMAL or FAIL

      NORMAL: Transponder key coil is normal

      FAIL: Transponder key coil is malfunctioning

      		 -
      OK
      NORMAL (transponder key coil is normal) appears on screen.

    OK

    REPLACE TRANSPONDER KEY ECU

    NG

  4. CHECK HARNESS AND CONNECTOR (TRANSPONDER KEY ECU - TRANSPONDER KEY AMPLIFIER)


    1. A01BAY7E57

      Disconnect the H60 transponder key ECU connector.

    2. Disconnect the H43 transponder key amplifier connector.

    3. Check the resistance.

      Standard resistance (Check for open)
      Tester Connection Specified Condition
      H60-14 (VC5) - H43-1 (VC5) Below 1 Ω
      H60-15 (CODE) - H43-4 (CODE)
      H60-4 (TXCT) - H43-5 (TXCT)
      H60-5 (AGND) - H43-7 (AGND)
      Standard resistance (Check for short)
      Tester Connection Specified Condition
      H60-14 (VC5) or H43-1 (VC5) - Body ground 10 kΩ or higher
      H60-15 (CODE) or H43-4 (CODE) - Body ground
      H60-4 (TXCT) or H43-5 (TXCT) - Body ground

    4. Reconnect the transponder key amplifier connector.

    5. Reconnect the transponder key ECU connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. CHECK TRANSPONDER KEY AMPLIFIER (OPERATION)


    1. After replacing the transponder key amplifier with a normally functioning amplifier, check that the engine starts.

      OK
      Engine starts.

    NG

    REPLACE TRANSPONDER KEY ECU

    OK

    END (TRANSPONDER KEY AMPLIFIER DEFECTIVE)