SMART ENTRY AND START SYSTEM (for Entry Function), Diagnostic DTC:B27A8

DTC Code DTC Name
B27A8 Open in Outside Luggage Compartment Electrical Key Antenna Circuit

DESCRIPTION

When the trigger switch is pressed, the certification ECU (smart key control ECU assembly) generates a request signal and sends it through the electrical key antenna (back door). The electrical key antenna transmits the received signal within an area of approximately 0.7 m (2.30 ft.) from the back door in order to detect the person carrying the electrical key transmitter sub-assembly.

DTC B27A8 is stored by the certification ECU (smart key ECU assembly) when an open circuit is detected between the certification ECU (smart key ECU assembly) and electrical key antenna (back door) (between terminals CLG8 and ANTE8, or terminals CG8B and CLGB).

DTC Code DTC Detection Condition Trouble Area DTC Output Confirmation Operation
B27A8 An open circuit is detected in the circuit between the certification ECU (smart key ECU assembly) and electrical key antenna (back door) (CLG8 - ANTE8, CG8B - CLGB) (1 trip detection logic*).

  • Harness or connector

  • Electrical key antenna assembly (back door)

  • Certification ECU (smart key ECU assembly)

 Any time

Vehicle Condition and Fail-safe Operation when Malfunction Detected
Vehicle Condition when Malfunction Detected Fail-safe Operation when Malfunction Detected
Entry lock/unlock operation cannot be performed for back door -
Related Data List and Active Test
DTC Code Data List and Active Test
B27A8 Key diagnostic mode can be used to perform troubleshooting

WIRING DIAGRAM

A003CYQE40

INSPECTION PROCEDURE

Note


  • The smart entry and start system (for Entry Function) uses a multiplex communication system (LIN communication system) and the CAN communication system. Inspect the communication function by following How to Proceed with Troubleshooting Click here. Troubleshoot the smart entry and start system (for Entry Function) after confirming that the communication systems are functioning properly.

  • When using the GTS with the vehicle engine switch off, connect the GTS to the vehicle 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 the Model Code "KEY REGIST" under manual mode and enter the following menus: Body Electrical / Entry&Start(CAN). 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.

  • Before replacing the certification ECU (smart key ECU assembly), refer to the smart entry and start system (for Entry Function) precaution Click here.

  • After repair, confirm that no DTCs are output by performing the "DTC Output Confirmation Operation".

PROCEDURE


  1. CHECK CONNECTOR CONNECTION


    1. Turn the engine switch off.

    2. Check that the connectors are properly connected to the certification ECU (smart key ECU assembly) and electrical key antenna (back door).

      OK
      Connectors are properly connected.

    NG

    CONNECT CONNECTORS PROPERLY

    OK

  2. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU [SMART KEY ECU ASSEMBLY] - ELECTRICAL KEY ANTENNA [BACK DOOR])


    1. Disconnect the B76 certification ECU (smart key ECU assembly) connector.

    2. Disconnect the S1 electrical key antenna (back door) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      B76-8 (CLG8) - S1-2 (ANTE8) Always Below 1 Ω
      B76-24 (CG8B) - S1-1 (CLGB) Always Below 1 Ω
      B76-8 (CLG8) or S1-2 (ANTE8) - Body ground Always 10 kΩ or higher
      B76-24 (CG8B) or S1-1 (CLGB) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) (OUTPUT TO ELECTRICAL KEY ANTENNA [BACK DOOR])


    1. Connect the B76 certification ECU (smart key ECU assembly) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      B75-10 (E) - Body ground Always Below 1 Ω

    3. Using an oscilloscope, check the waveform.

      A003CMRE10
      Text in Illustration
      *a

      Component with harness connected

      (Certification ECU [Smart Key ECU Assembly])

      		 *b Waveform 1
      *c Trigger switch ON - -
      OK
      Tester Connection Condition Tool Setting Specified Condition
      B76-8 (CLG8) - B75-10 (E)

      Procedure:


      1. Engine switch off

      2. All doors closed

      		 - Not pulse generation

      Procedure:


      1. Engine switch off

      2. All doors closed

      3. While carrying the electrical key transmitter sub-assembly, press the trigger switch on the license plate light assembly.

      		 2 V/DIV., 500 ms./DIV. Pulse generation (See waveform 1)
      B76-24 (CG8B) - B75-10 (E)

      Procedure:


      1. Engine switch off

      2. All doors closed

      		 - Not pulse generation

      Procedure:


      1. Engine switch off

      2. All doors closed

      3. While carrying the electrical key transmitter sub-assembly, press the trigger switch on the license plate light assembly.

      		 2 V/DIV., 500 ms./DIV. Pulse generation (See waveform 1)

    NG

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

    OK

  4. REPLACE ELECTRICAL KEY ANTENNA (BACK DOOR)


    1. Temporarily replace the electrical key antenna (back door) with a new or known good one Click here.


    NEXT

  5. CLEAR DTC


    1. Clear the DTCs Click here.


    NEXT

  6. CHECK FOR DTC


    1. Check for DTCs Click here.

      OK
      DTC B27A8 is not output.

    NG

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

    OK

    END (ELECTRICAL KEY ANTENNA [BACK DOOR] WAS DEFECTIVE)