DTC    B27A5    Open in Front Floor Electrical Key Oscillator Circuit

for Preparation Click here


DESCRIPTION

The certification ECU (smart key ECU assembly) generates a request signal and transmits the signal to the No. 1 indoor electrical key antenna assembly (front floor). For the No. 1 indoor electrical key antenna assembly (front 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 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 No. 1 indoor electrical key antenna assembly (front floor) (between terminals CLG5 and CLG3, or terminals CG5B and CLGB).

DTC Code
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 No. 1 indoor electrical key antenna assembly (front floor) (CLG5 - CLG3, CG5B - CLGB) (1 trip detection logic*).
  1. Harness or connector
  2. No. 1 indoor electrical key antenna assembly (front floor)
  3. Certification ECU (smart key ECU assembly)
Any time
  1. *: Only output while a malfunction is present.

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:
  1. Power source mode does not change when power switch pressed
  2. Key locked inside vehicle
-

Related Data List and Active Test 
DTC Code
Data List and Active Test
B27A5
Key diagnostic mode can be used to perform troubleshooting

WIRING DIAGRAM


B249967E28


INSPECTION PROCEDURE

NOTICE:
  1. The 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 entry and start system (for Entry Function) after confirming that the communication systems are functioning properly.
  2. When using the intelligent tester with the power 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.
  3. Before replacing the certification ECU (smart key ECU assembly), refer to the entry and start system (for Entry Function) (Click here).
  4. After repair, confirm DTC not reoccur with performing the "DTC Output Confirmation Operation".
  5. No. 1 indoor electrical key antenna assembly (front floor) has an antenna coil between CLG3 and CLGB terminals.

1.CHECK CONNECTOR CONNECTION

  1. Turn the power switch off.

  1. Check that the connectors are properly connected to the certification ECU (smart key ECU assembly) and No. 1 indoor electrical key antenna assembly (front floor).

    OK:
    Connectors are properly connected.



NG
CONNECT CONNECTORS PROPERLY
OK


2.CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - NO. 1 INDOOR ELECTRICAL KEY ANTENNA)

  1. Disconnect the H1 certification ECU (smart key ECU assembly) connector.

  1. Disconnect the H74 No. 1 indoor electrical key antenna assembly (front floor) connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    H1-7 (CLG5) - H74-1 (CLG3)
    		Always
    		Below 1 Ω
    H1-8 (CG5B) - H74-3 (CLGB)
    		Always
    		Below 1 Ω
    H1-15 (E) - Body ground
    		Always
    		Below 1 Ω
    H1-7 (CLG5) or H74-1 (CLG3) - Body ground
    		Always
    		10 kΩ or higher
    H1-8 (CG5B) or H74-3 (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 NO. 1 INDOOR ELECTRICAL KEY ANTENNA [FRONT FLOOR])


  1. Connect the H1 certification ECU (smart key ECU assembly) connector.


    B250849E23


    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
    		-
    		-

  1. Connect the H74 No. 1 indoor electrical key antenna assembly (front floor) connector.

  1. Using an oscilloscope, check the waveform.

    OK:

    Tester Connection
    		Switch Condition
    		Tool Setting
    		Specified Condition
    H1-7 (CLG5) - H1-15 (E)
    		Procedure:
    1. Power switch off
    2. Key not inside vehicle
    3. Door is open
    4. Door is closed
    5. 30 seconds elapse
    		2 V/DIV., 500 ms/DIV.
    		Pulse generation (See waveform)
    H1-8 (CG5B) - H1-15 (E)
    		Procedure:
    1. Power switch off
    2. Key not inside vehicle
    3. Door is open
    4. Door is closed
    5. 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. 1 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY (FRONT FLOOR)

  1. Temporarily replace the No. 1 indoor electrical key antenna assembly (front 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 B27A5 is not output.



NG
REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)
OK

END (NO. 1 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY WAS DEFECTIVE)