Click here

SMART ENTRY AND START SYSTEM(for Entry Function), Diagnostic DTC:B27A4

Click here
Click here
DTC Code DTC Name
B27A4 Open in Rear Door Electrical Antenna Circuit, Front Passengers Side
Click here

DESCRIPTION

The certification ECU (smart key ECU assembly) generates a request signal and transmits the signal to the rear door outside handle assembly (for rear door) [electrical key antenna] at intervals of 0.25 seconds. For the rear door outside handle assembly (for rear 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 rear door at intervals of 0.25 seconds. DTC B27A4 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 rear door outside handle assembly (for rear door) [electrical key antenna] (between terminals CLG4 and ANT1, or terminals CG4B and ANT2).

DTC Code DTC Detection Condition Trouble Area DTC Output Confirmation Operation
B27A4 An open circuit is detected in the circuit between the certification ECU (smart key ECU assembly) and rear door outside handle assembly (for rear door) (CLG4 - ANT1, CG4B - ANT2) (1 trip detection logic*).

  • Harness or connector

  • Rear door outside handle assembly (for rear door)

  • Certification ECU (smart key ECU assembly)

 Any time

Table 1. 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 rear door -
Table 2. Related Data List and Active Test
DTC Code Data List and Active Test
B27A4 Key diagnostic mode can be used to perform troubleshooting
A0008GXE71
Click here

WIRING DIAGRAM

Click here

CAUTION / NOTICE / HINT

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 power 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".

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

Click here

PROCEDURE


  1. Click here

    CHECK CONNECTOR CONNECTION


    1. Turn the power switch off.

    2. Check that the connectors are properly connected to the certification ECU (smart key ECU assembly) and rear door outside handle assembly (for rear door).

      OK
      Connectors are properly connected.

  2. Click here

    CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - REAR DOOR OUTSIDE HANDLE ASSEMBLY AND BODY GROUND)


    1. Disconnect the A72 and Q37 certification ECU (smart key ECU assembly) connectors.

    2. Disconnect the N8*1 or O8*2 rear door outside handle assembly (for rear door) connector.


      • *1: for LHD

      • *2: for RHD

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

      Standard Resistance
      Table 3. for LHD
      Tester Connection Condition Specified Condition
      Q37-3 (CLG4) - N8-6 (ANT1) Always Below 1 Ω
      Q37-4 (CG4B) - N8-3 (ANT2) Always Below 1 Ω
      A72-11 (E) - Body ground Always Below 1 Ω
      N8-2 (GND) - Body ground Always Below 1 Ω
      Q37-3 (CLG4) or N8-6 (ANT1) - Body ground Always 10 kΩ or higher
      Q37-4 (CG4B) or N8-3 (ANT2) - Body ground Always 10 kΩ or higher
      Table 4. for RHD
      Tester Connection Condition Specified Condition
      Q37-12 (CLG3) - O8-6 (ANT1) Always Below 1 Ω
      Q37-13 (CG3B) - O8-3 (ANT2) Always Below 1 Ω
      A72-11 (E) - Body ground Always Below 1 Ω
      O8-2 (GND) - Body ground Always Below 1 Ω
      Q37-12 (CLG3) or O8-6 (ANT1) - Body ground Always 10 kΩ or higher
      Q37-13 (CG3B) or O8-3 (ANT2) - Body ground Always 10 kΩ or higher

    • OKClick here
    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR

  3. Click here

    CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) (OUTPUT TO REAR SIDE ELECTRICAL KEY ANTENNA)


    1. A0006QZE02

      Connect the A72 and Q37 certification ECU (smart key ECU assembly) connectors.

      Table 5. Text in Illustration
      *A for LHD *B for RHD
      *1 Waveform 1 *2 Waveform 2
      *a

      Component with harness connected

      (Certification ECU (Smart Key ECU Assembly))

      		 - -

    2. Connect the N8*3 or O8*4 rear door outside handle assembly (for rear door) connector.

    3. Using an oscilloscope, check the waveform.

      OK
      Table 6. for LHD
      Tester Connection Condition Tool Setting Specified Condition
      Q37-3 (CLG4) - A72-11 (E)

      Procedure:


      1. Power 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)
      Q37-3 (CLG4) - A72-11 (E)

      Procedure:


      1. Power 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)
      Q37-4 (CG4B) - A72-11 (E)

      Procedure:


      1. Power 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)
      Table 7. for RHD
      Tester Connection Condition Tool Setting Specified Condition
      Q37-12 (CLG3) - A72-11 (E)

      Procedure:


      1. Power 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)
      Q37-12 (CLG3) - A72-11 (E)

      Procedure:


      1. Power 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)
      Q37-13 (CG3B) - A72-11 (E)

      Procedure:


      1. Power 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


    • OKClick here
    • NG

      REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

  4. Click here

    REPLACE REAR DOOR OUTSIDE HANDLE ASSEMBLY (FOR REAR DOOR)


    1. Temporarily replace the rear door outside handle assembly (for rear door) with a new or known good one (Click here).


  5. Click here

    CLEAR DTC


    1. Clear the DTCs (Click here).


  6. Click here

    CHECK FOR DTC


    1. Check for DTCs (Click here).

      OK
      DTC B27A4 is not output.

    • OK

      END (REAR DOOR OUTSIDE HANDLE ASSEMBLY (FOR REAR DOOR) WAS DEFECTIVE)

    • NG

      REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)