Toyota Avalon (XX50): Additional Key cannot be Registered. Open in Front Floor Electrical Key Oscillator Circuit (B27A5). Open in Rear Floor Electrical Key Oscillator Circuit (B27A6)

Toyota Avalon (XX50) 2019-2022 Service & Repair Manual / Vehicle Interior / Theft Deterrent / Keyless Entry / Smart Key System(for Start Function, Hv Model) / Additional Key cannot be Registered. Open in Front Floor Electrical Key Oscillator Circuit (B27A5). Open in Rear Floor Electrical Key Oscillator Circuit (B27A6)

Additional Key cannot be Registered

DESCRIPTION

If additional registration is not possible, a malfunction of the electrical key transmitter sub-assembly, certification ECU (smart key ECU assembly), power switch, No. 1 indoor electrical key antenna assembly (front floor), steering lock ECU (steering lock actuator or upper bracket assembly) or door control receiver is suspected.

CAUTION / NOTICE / HINT

NOTICE:

If registration of an electrical key transmitter sub-assembly cannot be performed, refer to Registration.
Click here
When using the Techstream with the power switch off, connect the Techstream to the DLC3 and turn a courtesy light switch on and off at intervals of 1.5 seconds or less until communication between the Techstream and the vehicle begins. Then select the vehicle type under manual mode and enter the following menus: Body Electrical / Smart Key. While using the Techstream, periodically turn a courtesy light switch on and off at intervals of 1.5 seconds or less to maintain communication between the Techstream and the vehicle.
The smart key system (for Start Function, HV Model) uses the LIN communication system and CAN communication system. Inspect the communication function by following How to Proceed with Troubleshooting. Troubleshoot the smart key system (for Start Function, HV Model) after confirming that the communication systems are functioning properly.
Click here
Before replacing the certification ECU (smart key ECU assembly), steering lock ECU (steering lock actuator or upper bracket assembly) or electrical key transmitter sub-assembly, refer to Registration.
Click here
After repair, confirm that no DTCs are output.

HINT:

When additional registration is not possible, freeze frame data may be stored in the certification ECU (smart key ECU assembly).

Click here

PROCEDURE

1.	CHECK FOR DTC

(a) Check for DTCs.

Body Electrical > Smart Key > Trouble Codes

NOTICE:

If a malfunction occurs, do not remove/install the vehicle auxiliary battery before checking for DTCs.

OK:

DTCs are not output.

GO TO DIAGNOSTIC TROUBLE CODE CHART

2.	READ VALUE USING TECHSTREAM (UNMATCHED VEHICLE-ID)

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(d) Enter the following menus: Body Electrical / Smart Key / Data List.

(e) Read the Data List according to the display on the Techstream.

Body Electrical > Smart Key > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Unmatched Vehicle-ID	Key No. (incorrect or correct)	No or Yes	No: Communication normal Yes: Communication malfunction	The vehicle ID registered in the vehicle and the vehicle ID registered in the electrical key transmitter sub-assembly are different (if a key from another vehicle is brought into the vehicle exterior detection area while the doors are locked, "Yes" is displayed for "Unmatched Vehicle-ID" in the Data List). Other potential causes: An electrical key transmitter sub-assembly from a different vehicle is being used. A communication error due to wave interference. The electrical key transmitter sub-assembly or certification ECU (smart key ECU assembly) is malfunctioning.

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Unmatched Vehicle-ID

Key No. (incorrect or correct)

No or Yes

No: Communication normal

Yes: Communication malfunction

The vehicle ID registered in the vehicle and the vehicle ID registered in the electrical key transmitter sub-assembly are different (if a key from another vehicle is brought into the vehicle exterior detection area while the doors are locked, "Yes" is displayed for "Unmatched Vehicle-ID" in the Data List).

Other potential causes:

An electrical key transmitter sub-assembly from a different vehicle is being used.
A communication error due to wave interference.
The electrical key transmitter sub-assembly or certification ECU (smart key ECU assembly) is malfunctioning.

Body Electrical > Smart Key > Data List

Tester Display
Unmatched Vehicle-ID

Result	Proceed to
"No" is displayed	A
"Yes" is displayed	B

GO TO STEP 5

3.	CHECK SMART KEY SYSTEM (for Start Function, HV Model)

(a) Remove the transmitter battery from the electrical key transmitter sub-assembly.

(b) With the brake pedal depressed, hold the electrical key transmitter sub-assembly near the power switch and check if the power source mode changes.

OK:

The power source mode changes.

HINT:

If the power source mode changes, the cabin verification is malfunctioning.

*1	Power Switch
*2	Electrical Key Transmitter Sub-assembly

Result	Proceed to
The power source mode changes	A
The power source mode does not change	B

GO TO SMART KEY SYSTEM (for Start Function, HV Model) (Power Source Mode does not Change to ON (IG and ACC))

4.	CHECK STEERING LOCK FUNCTION

(a) The power switch is on (ACC) or on (IG).

(b) Check that the steering unlocks.

HINT:

When the power switch is turned on (ACC) or on (IG) and the electrical key transmitter assembly and certification ECU (smart key ECU assembly) are verified, the steering is unlocked.

Check that the communication between the steering lock ECU (steering lock actuator or upper bracket assembly) and certification ECU (smart key ECU assembly) is normal.

OK:

The steering unlocks.

GO TO SMART KEY SYSTEM (for Start Function, HV Model) (Unable to Unlock Steering Wheel (Hybrid Control System cannot Start))

5.	REGISTRATION

(a) Using an unregistered electrical key transmitter sub-assembly, perform the additional registration procedure.

Click here

OK:

Additional registration can be completed.

REPLACE ELECTRICAL KEY TRANSMITTER SUB-ASSEMBLY (FIRST REGISTERED KEY WAS DEFECTIVE)

6.	REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

(a) Temporarily replace the certification ECU (smart key ECU assembly) with a new one and register the electrical key transmitter sub-assemblies.

HINT:

For replacement.
Click here
For registration.
Click here

OK:

All of the electrical key transmitter sub-assemblies could be registered to the new certification ECU (smart key ECU assembly) successfully.

END (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) WAS DEFECTIVE)

GO TO OTHER PROBLEM (New key cannot be Registered)

Open in Front Floor Electrical Key Oscillator Circuit (B27A5)

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 electrical key transmitter sub-assembly is in the cabin, the signal from the certification ECU (smart key ECU assembly) requesting a response from the electrical key transmitter sub-assembly is transmitted inside the vehicle. DTC B27A5 is stored by the certification ECU (smart key ECU assembly) when an open is detected between the certification ECU (smart key ECU assembly) and No. 1 indoor electrical key antenna assembly (front floor) (between terminals CLG5 and ANTE5, or terminals CG5B and CLGB).

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	Note
B27A5	Open in Front Floor Electrical Key Oscillator Circuit	An open is detected in the circuit between the certification ECU (smart key ECU assembly) and No. 1 indoor electrical key antenna assembly (front floor) (CLG5 - ANTE5, CG5B - CLGB) (1 trip detection logic*).	Certification ECU (smart key ECU assembly) No. 1 indoor electrical key antenna assembly (front floor) Wire harness or connector	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
When electrical key transmitter sub-assembly is in front seat area: Power source mode does not change when power switch pressed Electrical key transmitter sub-assembly locked inside vehicle	-

Vehicle Condition when Malfunction Detected

Fail-safe Operation when Malfunction Detected

When electrical key transmitter sub-assembly is in front seat area:

Power source mode does not change when power switch pressed
Electrical key transmitter sub-assembly 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

CAUTION / NOTICE / HINT

NOTICE:

When using the Techstream with the power switch off, connect the Techstream to the DLC3 and turn a courtesy light switch on and off at intervals of 1.5 seconds or less until communication between the Techstream and the vehicle begins. Then select the vehicle type under manual mode and enter the following menus: Body Electrical / Smart Key. While using the Techstream, periodically turn a courtesy light switch on and off at intervals of 1.5 seconds or less to maintain communication between the Techstream and the vehicle.
The smart key system (for Start Function, HV Model) uses the LIN communication system and CAN communication system. Inspect the communication function by following How to Proceed with Troubleshooting. Troubleshoot the smart key system (for Start Function, HV Model) after confirming that the communication systems are functioning properly.
Click here
Before replacing the certification ECU (smart key ECU assembly), refer to Registration.
Click here
After repair, confirm that no DTCs are output by performing "DTC Output Confirmation Operation".

PROCEDURE

1.	CHECK CONNECTOR CONNECTION

(a) 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.

CONNECT CONNECTORS PROPERLY

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

(a) Disconnect the G40 certification ECU (smart key ECU assembly) connector.

(b) Disconnect the G42 No. 1 indoor electrical key antenna assembly (front floor) connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
G40-8 (CLG5) - G42-1 (ANTE5)	Always	Below 1 Ω
G40-9 (CG5B) - G42-3 (CLGB)	Always	Below 1 Ω

(d) Reconnect the G40 certification ECU (smart key ECU assembly) connector.

REPAIR OR REPLACE HARNESS OR CONNECTOR

3.	CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) (OUTPUT TO NO. 1 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY (FRONT FLOOR))

Component with harness connected

(Certification ECU (Smart Key ECU Assembly))

Waveform

For 30 seconds after any door closed

After 30 seconds or more have elapsed since any door closed

(a) Using an oscilloscope, check the waveform.

OK:

Tester Connection	Condition	Tool Setting	Specified Condition
G40-8 (CLG5) - G40-18 (E)	Procedure: Power switch off Electrical key transmitter sub-assembly not inside vehicle Within 30 seconds of closing any door	2 V/DIV., 500 ms/DIV.	Pulse generation (See waveform)
G40-9 (CG5B) - G40-18 (E)	Procedure: Power switch off Electrical key transmitter sub-assembly not inside vehicle Within 30 seconds of closing any door	2 V/DIV., 500 ms/DIV.	Pulse generation (See waveform)

Tester Connection

Condition

Tool Setting

Specified Condition

G40-8 (CLG5) - G40-18 (E)

Procedure:

Power switch off
Electrical key transmitter sub-assembly not inside vehicle
Within 30 seconds of closing any door

2 V/DIV., 500 ms/DIV.

Pulse generation

(See waveform)

G40-9 (CG5B) - G40-18 (E)

Procedure:

Power switch off
Electrical key transmitter sub-assembly not inside vehicle
Within 30 seconds of closing any door

2 V/DIV., 500 ms/DIV.

Pulse generation

(See waveform)

REPLACE NO. 1 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY (FRONT FLOOR)

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

Open in Rear Floor Electrical Key Oscillator Circuit (B27A6)

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 (rear floor). For the No. 1 indoor electrical key antenna assembly (rear floor) to detect when the electrical key transmitter sub-assembly is in the cabin, the signal from the certification ECU (smart key ECU assembly) requesting a response from the electrical key transmitter sub-assembly is transmitted inside the vehicle. DTC B27A6 is stored by the certification ECU (smart key ECU assembly) when an open is detected between the certification ECU (smart key ECU assembly) and No. 1 indoor electrical key antenna assembly (rear floor) (between terminals CLG6 and ANTE6, or terminals CG6B and CLGB).

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	Note
B27A6	Open in Rear Floor Electrical Key Oscillator Circuit	An open is detected in the circuit between the certification ECU (smart key ECU assembly) and No. 1 indoor electrical key antenna assembly (rear floor) (CLG6 - ANTE6, CG6B - CLGB) (1 trip detection logic*).	Certification ECU (smart key ECU assembly) No. 1 indoor electrical key antenna assembly (rear floor) Wire harness or connector	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
When electrical key transmitter sub-assembly is in rear seat area: Power source mode does not change when power switch pressed Electrical key transmitter sub-assembly locked inside vehicle	-

Vehicle Condition when Malfunction Detected

Fail-safe Operation when Malfunction Detected

When electrical key transmitter sub-assembly is in rear seat area:

Power source mode does not change when power switch pressed
Electrical key transmitter sub-assembly locked inside vehicle

Related Data List and Active Test

DTC No.	Data List and Active Test
B27A6	Key diagnostic mode can be used to perform troubleshooting

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

When using the Techstream with the power switch off, connect the Techstream to the DLC3 and turn a courtesy light switch on and off at intervals of 1.5 seconds or less until communication between the Techstream and the vehicle begins. Then select the vehicle type under manual mode and enter the following menus: Body Electrical / Smart Key. While using the Techstream, periodically turn a courtesy light switch on and off at intervals of 1.5 seconds or less to maintain communication between the Techstream and the vehicle.
The smart key system (for Start Function, HV Model) uses the LIN communication system and CAN communication system. Inspect the communication function by following How to Proceed with Troubleshooting. Troubleshoot the smart key system (for Start Function, HV Model) after confirming that the communication systems are functioning properly.
Click here
Before replacing the certification ECU (smart key ECU assembly), refer to Registration.
Click here
After repair, confirm that no DTCs are output by performing "DTC Output Confirmation Operation".

PROCEDURE

1.	CHECK CONNECTOR CONNECTION

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

OK:

Connectors are properly connected.

CONNECT CONNECTORS PROPERLY

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

(a) Disconnect the K10 certification ECU (smart key ECU assembly) connector.

(b) Disconnect the K12 No. 1 indoor electrical key antenna assembly (rear floor) connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
K10-5 (CLG6) - K12-1 (ANTE6)	Always	Below 1 Ω
K10-6 (CG6B) - K12-3 (CLGB)	Always	Below 1 Ω

(d) Reconnect the K10 certification ECU (smart key ECU assembly) connector.

REPAIR OR REPLACE HARNESS OR CONNECTOR

3.	CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) (OUTPUT TO NO. 1 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY (REAR FLOOR))

Component with harness connected

(Certification ECU (Smart Key ECU Assembly))

Waveform

For 30 seconds after any door closed

After 30 seconds or more have elapsed since any door closed

(a) Using an oscilloscope, check the waveform.

OK:

Tester Connection

Condition

Tool Setting

Specified Condition

K10-5 (CLG6) - G40-18 (E)

Procedure:

Power switch off
Electrical key transmitter sub-assembly not inside vehicle
Within 30 seconds of closing any door

2 V/DIV., 500 ms/DIV.

Pulse generation

(See waveform)

K10-6 (CG6B) - G40-18 (E)

Procedure:

Power switch off
Electrical key transmitter sub-assembly not inside vehicle
Within 30 seconds of closing any door

2 V/DIV., 500 ms/DIV.

Pulse generation

(See waveform)

REPLACE NO. 1 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY (REAR FLOOR)

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

Smart Key System(for Start Function, Hv Model)

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