PUSH-BUTTON START SYSTEM, Diagnostic DTC:B27A6

DTC Code DTC Name
B27A6 Open in Rear Floor Electrical Key Oscillator Circuit

DESCRIPTION

The certification ECU (smart key ECU assembly) generates a request signal and transmits the signal to the No. 2 indoor electrical key antenna assembly (rear floor). For the No. 2 indoor electrical key antenna assembly (rear floor) 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 B27A6 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 No. 2 indoor electrical key antenna assembly (rear floor) (between terminals CLG6 and CLG4, or terminals CG6B and CLGB).

DTC Code DTC Detection Condition Trouble Area DTC Output Confirmation Operation
B27A6 An open circuit is detected in the circuit between the certification ECU (smart key ECU assembly) and No. 2 indoor electrical key antenna assembly (rear floor) (CLG6 - CLG4, CG6B - CLGB) (1 trip detection logic*).

  • Wire harness or connector

  • No. 2 indoor electrical key antenna assembly (rear floor)

  • 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

When key is in rear seat area:


  • Power source mode does not change when power switch pressed

  • Key locked inside vehicle

 -
Related Data List and Active Test
DTC Code Data List and Active Test
B27A6 Key diagnostic mode can be used to perform troubleshooting

WIRING DIAGRAM

A003W3QE34

INSPECTION PROCEDURE

Note


  • When using the intelligent tester with the power switch off, perform either of the following: 1) Turn a courtesy light switch on and off at intervals of 1.5 seconds or less until communication between the intelligent tester and vehicle begins, or 2) connect the intelligent tester to the vehicle, select the vehicle type under manual mode, and then enter the following menus:

    for Power Source Control: Body / Power Source Control / DTC.

    for Entry&Start: Body / Entry&Start / DTC.

  • The push-button start system uses multiplex communication. First perform the inspections in "How to Proceed with Troubleshooting" to confirm that there are no communication malfunctions before proceeding with troubleshooting Click here

  • After performing repairs, perform the operation that fulfills the DTC output confirmation operation, and then confirm that no DTCs are output again.

  • When replacing the certification ECU (smart key ECU assembly), registration must be performed refer to the Service Bulletin.

  • No. 2 indoor electrical key antenna assembly (rear floor) has an antenna coil between CLG4 and CLGB terminals.

PROCEDURE


  1. 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 No. 2 indoor electrical key antenna assembly (rear floor).

      OK
      Connectors are properly connected.

    NG

    CONNECT CONNECTORS PROPERLY

    OK

  2. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - NO. 2 INDOOR ELECTRICAL KEY ANTENNA)


    1. Disconnect the H143 certification ECU (smart key ECU assembly) connector.

    2. Disconnect the P8 No. 2 indoor electrical key antenna assembly (rear floor) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H143-24 (CLG6) - P8-1 (CLG4) Always Below 1 Ω
      H143-25 (CG6B) - P8-3 (CLGB) Always Below 1 Ω
      H143-15 (E) - Body ground Always Below 1 Ω
      H143-24 (CLG6) or P8-1 (CLG4) - Body ground Always 10 kΩ or higher
      H143-25 (CG6B) or P8-3 (CLGB) - Body ground Always 10 kΩ or higher

    NG

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

    OK

  3. CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) (OUTPUT TO NO. 2 INDOOR ELECTRICAL KEY ANTENNA [REAR FLOOR])


    1. Connect the H143 certification ECU (smart key ECU assembly) connector.

      A003YFWE27
      Text in Illustration
      *1 Waveform - -
      *a

      Component with harness connected

      (Certification ECU (smart key ECU assembly))

      		 *b Door open
      *c After approximately 30 seconds from when the door is closed - -

    2. Connect the P8 No. 2 indoor electrical key antenna assembly (rear floor) connector.

    3. Using an oscilloscope, check the waveform.

      OK
      Tester Connection Switch Condition Tool Setting Specified Condition
      H143-24 (CLG6) - H143-15 (E)

      Procedure:


      1. Power switch off

      2. Door is open

      3. Door is closed

      4. 30 seconds elapse

      		 2 V/DIV., 500 ms/DIV. Pulse generation (See waveform)
      H143-25 (CG6B) - H143-15 (E)

      Procedure:


      1. Power switch off

      2. Door is open

      3. Door is closed

      4. 30 seconds elapse

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

    NG

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

    OK

  4. REPLACE NO. 2 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY (REAR FLOOR)


    1. Temporarily replace the No. 2 indoor electrical key antenna assembly (rear floor) with a new or normally functioning 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 B27A6 is not output.

    NG

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

    OK

    END (NO. 2 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY WAS DEFECTIVE)