ENTRY AND START SYSTEM(for Entry Function), Diagnostic DTC:B27A5

DTC Code DTC Name
B27A5 Open in Front Floor Electrical Key Oscillator Circuit

DESCRIPTION

The certification ECU (smart key ECU assembly) generates a request signal and transmits the signal to the indoor electrical key oscillator (front floor). For the certification ECU (smart key ECU assembly) to detect when the key is inside the vehicle, the signal from the certification ECU (smart key ECU assembly) requesting a response from the key is transmitted inside the vehicle. DTC B27A5 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 indoor electrical key oscillator (front floor) (between terminals CLG5 and ANTE5, or terminals CG5B and CLGB).

DTC No. DTC Detection Condition Trouble Area DTC Output Confirmation Operation
B27A5 An open circuit is detected in the circuit between the certification ECU (smart key ECU assembly) and indoor electrical key oscillator (front floor) (CLG5 - ANTE5, CG5B - CLGB) (1 trip detection logic*1).

  • Wire harness or connector

  • indoor electrical key oscillator (front floor)

  • Certification ECU (smart key ECU assembly)

 Any time*2

Vehicle Condition and Fail-safe Operation when Malfunction Detected
Vehicle Condition when Malfunction Detected Fail-safe Operation when Malfunction Detected

When key is in front seat area:


  • Power source mode does not change when engine switch pressed

  • Key locked inside vehicle

 -
Related Data List and Active Test
DTC No. Data List and Active Test
B27A5 Key diagnostic mode can be used to perform troubleshooting

WIRING DIAGRAM

A004J3GE90
*a Certification ECU (Smart Key ECU Assembly)
*b Indoor Electrical Key Oscillator (Front Floor)

CAUTION / NOTICE / HINT

Note


  • When using the GTS with the engine switch off to troubleshoot:

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

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

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

  • After repair, confirm DTC does not reoccur by performing the "DTC Output Confirmation Operation".

  • Indoor electrical key oscillator (front floor) has an antenna coil between CLG3 and CLGB terminals.

PROCEDURE


  1. CHECK CONNECTOR CONNECTION CONDITION


    1. Turn the engine switch off.

    2. Check that the connectors are properly connected to the certification ECU (smart key ECU assembly) and the indoor electrical key oscillator (front floor).

      OK
      Connectors are properly connected.

    NG

    CONNECT CONNECTORS PROPERLY

    OK

  2. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - INDOOR ELECTRICAL KEY OSCILLATOR (FRONT FLOOR))


    1. Disconnect the D41 and D48 certification ECU (smart key ECU assembly) connectors.

    2. Disconnect the D26 indoor electrical key oscillator (front floor) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      D41-3 (CLG5) - D26-1 (ANTE5) Always Below 1 Ω
      D41-2 (CG5B) - D26-3 (CLGB) Always Below 1 Ω
      D48-11 (GND) - Body ground Always Below 1 Ω
      D41-3 (CLG5) - Body ground Always 10 kΩ or higher
      D41-2 (CG5B) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. INSPECT CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) (OUTPUT TO INDOOR ELECTRICAL KEY OSCILLATOR (FRONT FLOOR))

    A004J0DE02
    Text in Illustration
    *a

    Component with harness connected

    (Certification ECU (smart key ECU assembly))

    		 *b Waveform
    *c Within approximately 30 seconds from when the door is closed *d After approximately 30 seconds from when the door is closed

    1. Reconnect the D41 and D48 certification ECU (smart key ECU assembly) connector.

    2. Reconnect the D26 indoor electrical key oscillator (front floor) connector.

    3. Using an oscilloscope, check the waveform.

      Tech Tips

      Check that the entry cancel function, which is one of the customizing settings of the entry and start system, is not set Click here.

      OK
      Tester Connection Switch Condition Tool Setting Specified Condition
      D41-3 (CLG5) - D48-11 (GND)

      Procedure:


      1. Engine switch off

      2. Door is open

      3. Door is closed

      4. 30 seconds elapse

      5. Electrical key transmitter sub-assembly not inside vehicle

      		 2 V/DIV., 500 ms/DIV.

      Pulse generation

      (See waveform)
      D41-2 (CG5B) - D48-11 (GND)

      Procedure:


      1. Engine switch off

      2. Door is open

      3. Door is closed

      4. 30 seconds elapse

      5. Electrical key transmitter sub-assembly not inside vehicle

      		 2 V/DIV., 500 ms/DIV.

      Pulse generation

      (See waveform)

    NG

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

    OK

  4. REPLACE INDOOR ELECTRICAL KEY OSCILLATOR (FRONT FLOOR)


    1. Temporarily replace the indoor electrical key oscillator (front floor) with a new or normally functioning one Click here.


    NEXT

  5. CHECK DTC OUTPUT


    1. Clear the DTCs Click here.

    2. Recheck for DTCs Click here.

      OK
      DTC B27A5 is not output.

    OK

    END (INDOOR ELECTRICAL KEY OSCILLATOR (FRONT FLOOR) WAS DEFECTIVE)

    NG

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)