SMART ENTRY AND START SYSTEM (for Entry Function), Diagnostic DTC:B27A1

DTC Code DTC Name
B27A1 Open in Driver Side Electrical Antenna Circuit

DESCRIPTION

The certification ECU (smart key ECU assembly) generates a request signal and transmits the signal to the front door outside handle assembly (for driver door) [electrical key antenna] at intervals of 0.25 seconds. For the front door outside handle assembly (for driver door) [electrical key antenna] to detect when the electrical key transmitter sub-assembly is brought close to the vehicle, a signal requesting a response from the electrical key transmitter sub-assembly is transmitted within approximately 1 m (3.28 ft.) of the driver door at intervals of 0.25 seconds. DTC B27A1 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 front door outside handle assembly (for driver door) [electrical key antenna] (between terminals CLG1 and ANT1, or terminals CG1B and ANT2).

DTC Code DTC Detection Condition Trouble Area DTC Output Confirmation Operation
B27A1 An open circuit is detected in the circuit between the certification ECU (smart key ECU assembly) and front door outside handle assembly (for driver door) (CLG1 - ANT1, CG1B - ANT2) (This is detected by the malfunction detection circuit in the certification ECU (smart key ECU assembly)) (1 trip detection logic*).

  • Wire harness or connector

  • Front door outside handle assembly (for driver 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 driver door -
Related Data List and Active Test
DTC Code Data List and Active Test
B27A1 Key diagnostic mode can be used to perform troubleshooting

WIRING DIAGRAM

A01EV0ZE05

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 intelligent tester with the engine switch off to troubleshoot:

    Connect the intelligent tester to the DLC3 and turn a courtesy light switch on and off at 1.5-second intervals until communication between the intelligent tester and vehicle begins.

  • 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".

  • The front door outside handle assembly (for driver door) has an antenna coil between ANT1 and ANT2 terminals.

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 front door outside handle assembly (for driver door).

      OK
      Connectors are properly connected.

    NG

    CONNECT CONNECTORS PROPERLY

    OK

  2. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - FRONT DOOR OUTSIDE HANDLE)


    1. Disconnect the I78 and A43 certification ECU (smart key ECU assembly) connector.

    2. Disconnect the W1*1 or V1*2 front door outside handle assembly (for driver door) connector.

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


      • *1: for LHD

      • *2: for RHD

      Standard Resistance
      for LHD
      Tester Connection Condition Specified Condition
      I78-12 (CLG1) - W1-6 (ANT1) Always Below 1 Ω
      I78-13 (CG1B) - W1-3 (ANT2) Always Below 1 Ω
      A43-11 (E) - Body ground Always Below 1 Ω
      W1-2 (GND) - Body ground Always Below 1 Ω
      I78-12 (CLG1) or W1-6 (ANT1) - Body ground Always 10 kΩ or higher
      I78-13 (CG1B) or W1-3 (ANT2) - Body ground Always 10 kΩ or higher
      for RHD
      Tester Connection Condition Specified Condition
      I78-12 (CLG1) - V1-6 (ANT1) Always Below 1 Ω
      I78-13 (CG1B) - V1-3 (ANT2) Always Below 1 Ω
      A43-11 (E) - Body ground Always Below 1 Ω
      V1-2 (GND) - Body ground Always Below 1 Ω
      I78-12 (CLG1) or V1-6 (ANT1) - Body ground Always 10 kΩ or higher
      I78-13 (CG1B) or V1-3 (ANT2) - 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 DRIVER SIDE ELECTRICAL KEY ANTENNA)


    1. Connect the I78 and A43 certification ECU (smart key ECU assembly) connector.

      A01ET2CE03
      Text in Illustration
      *1 Waveform 1 *2 Waveform 2
      *a

      Component with harness connected

      (Certification ECU (smart key ECU assembly))

      		 - -

    2. Connect the W1*3 or V1*4 front door outside handle assembly (for driver door) connector.

    3. Using an oscilloscope, check the waveform.

      OK
      Tester Connection Switch Condition Tool Setting Specified Condition
      I78-12 (CLG1) - A43-11 (E)

      Procedure:


      1. Engine switch off

      2. Electrical key transmitter sub-assembly brought outside vehicle

      3. All doors closed

      4. Electrical key transmitter sub-assembly not inside vehicle

      5. Electrical key transmitter sub-assembly brought inside detection area*1

      6. All doors locked through wireless operation

      		 2 V/DIV., 500 ms/DIV. Pulse generation (See waveform 1)
      I78-12 (CLG1) - A43-11 (E)

      Procedure:


      1. Engine switch off

      2. Electrical key transmitter sub-assembly brought outside vehicle

      3. All doors closed

      4. Electrical key transmitter sub-assembly not inside vehicle

      5. Electrical key transmitter sub-assembly brought outside detection area*2

      6. All doors locked through wireless operation

      		 2 V/DIV., 500 ms/DIV. Pulse generation (See waveform 2)
      I78-13 (CG1B) - A43-11 (E)

      Procedure:


      1. Engine switch off

      2. Electrical key transmitter sub-assembly brought outside vehicle

      3. All doors closed

      4. Electrical key transmitter sub-assembly not inside vehicle

      5. All doors locked through wireless operation

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

      • *1: For details about the areas that are inside the entry function detection area, refer to Operation Check Click here.

      • *2: For details about the areas that are outside the entry function detection area, refer to Operation Check Click here.

      • *3: for LHD

      • *4: for RHD


    NG

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

    OK

  4. REPLACE FRONT DOOR OUTSIDE HANDLE ASSEMBLY (FOR DRIVER DOOR)


    1. Temporarily replace the front door outside handle assembly (for driver 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 B27A1 is not output.

    NG

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

    OK

    END (FRONT DOOR OUTSIDE HANDLE ASSEMBLY (FOR DRIVER DOOR) WAS DEFECTIVE)