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

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

DESCRIPTION

When the trigger switch is pressed, the certification ECU (smart key control ECU assembly) generates a request signal and sends it through the No. 1 indoor electrical key antenna assembly (front bumper RH). The electrical key antenna transmits the received signal within an area of approximately 0.7 m (2.30 ft.) from the driver side door in order to detect the person carrying the electrical key transmitter sub-assembly.

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 No. 1 indoor electrical key antenna assembly (front bumper RH) (between terminals CLG1 and ANTE1, or terminals CG1B and CLGB).

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 No. 1 indoor electrical key antenna assembly (front bumper RH) (CLG1 - ANTE1, CG1B - CLGB) (This is detected by the malfunction detection circuit in the certification ECU [smart key ECU assembly]) (1 trip detection logic*).	Harness or connector No. 1 indoor electrical key antenna assembly (front bumper RH) Certification ECU (smart key ECU assembly)	Any time

*: 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
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

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 GTS with the vehicle engine 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".

PROCEDURE

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 No. 1 indoor electrical key antenna assembly (front bumper RH).
  
  OK
  
  Connectors are properly connected.
NG
CONNECT CONNECTORS PROPERLY

OK

OK
Connectors are properly connected.

CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU [SMART KEY ECU ASSEMBLY] - NO. 1 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY [FRONT BUMPER RH])

Disconnect the B76 certification ECU (smart key ECU assembly) connector.
Disconnect the A40 No. 1 indoor electrical key antenna assembly (front bumper RH) connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
B76-31 (CLG1) - A40-1 (ANTE1)	Always	Below 1 Ω
B76-30 (CG1B) - A40-2 (CLGB)	Always	Below 1 Ω
B76-31 (CLG1) or A40-1 (ANTE1) - Body ground	Always	10 kΩ or higher
B76-30 (CG1B) or A40-2 (CLGB) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) (OUTPUT TO NO. 1 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY [FRONT BUMPER RH])

Connect the B76 certification ECU (smart key ECU assembly) connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
B75-10 (E) - Body ground	Always	Below 1 Ω

Using an oscilloscope, check the waveform.

Text in Illustration
*a	Component with harness connected (Certification ECU [Smart Key ECU Assembly])	*b	Waveform 1
*c	Trigger switch ON	-	-

Tester Connection	Condition	Tool Setting	Specified Condition
B76-31 (CLG1) - B75-10 (E)	Procedure: Engine switch off All doors closed	-	Not pulse generation
B76-31 (CLG1) - B75-10 (E)	Procedure: Engine switch off All doors closed While carrying the electrical key transmitter sub-assembly, press the trigger switch on the front door outside handle assembly RH.	2 V/DIV., 500 ms./DIV.	Pulse generation (See waveform 1)
B76-30 (CG1B) - B75-10 (E)	Procedure: Engine switch off All doors closed	-	Not pulse generation
B76-30 (CG1B) - B75-10 (E)	Procedure: Engine switch off All doors closed While carrying the electrical key transmitter sub-assembly, press the trigger switch on the front door outside handle assembly RH.	2 V/DIV., 500 ms./DIV.	Pulse generation (See waveform 1)

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

REPLACE NO. 1 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY (FRONT BUMPER RH)
1. Temporarily replace the No. 1 indoor electrical key antenna assembly (front bumper RH) with a new or known good one Click here.
NEXT
CLEAR DTC
1. Clear the DTCs Click here.
NEXT
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 (NO. 1 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY [FRONT BUMPER RH] WAS DEFECTIVE)