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, Gasoline 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), engine 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

  • The smart key system (for Start Function, Gasoline 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, Gasoline Model) after confirming that the communication systems are functioning properly.

    Click here

  • When using the Techstream with the engine 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.
  • 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).

If freeze frame data is available, it can be helpful in determining whether any parts were malfunctioning or not or narrowing down the suspected areas based on the table below.

Registration Function (Reason for Non-operation)

Parameter Name

Cause of Problem and Countermeasure

Failed Registration Mode

Make sure that another mode or a different registration mode is not selected, and then perform registration again.

Key Registration Max

Registration was not possible because the maximum number of the electrical key transmitter sub-assemblies has already been registered to the certification ECU (smart key ECU assembly).

If a new electrical key transmitter sub-assembly needs to be registered, such as when one of the registered electrical key transmitter sub-assemblies has been lost, erase an unnecessary ID code first.

Key Verification: Amp Abnormal

Although a registered electrical key transmitter sub-assembly was held near the engine switch, electrical key transmitter sub-assembly registration could not be confirmed due to a malfunction of the immobiliser amplifier, such as a short to ground. DTC B278A or B2784 was stored.

Key Verification: Read Error

A registered electrical key transmitter sub-assembly was not held near the engine switch properly or electrical key transmitter sub-assembly registration cannot be confirmed due to wave interference, etc.

Register the electrical key transmitter sub-assembly using the correct procedure or use another registered electrical key transmitter sub-assembly.

Transponder Key Amp Abnormal

Although an unregistered electrical key transmitter sub-assembly was held near the engine switch, electrical key transmitter sub-assembly registration cannot be completed due to a malfunction of the immobiliser amplifier, such as a short to ground. DTC B278A or B2784 was stored.

New Key Registration Error

An unregistered electrical key transmitter sub-assembly was not held near the engine switch properly or electrical key transmitter sub-assembly registration cannot be confirmed due to a malfunction, such as wave interference.

Reregister the electrical key transmitter sub-assembly using the correct procedure or use another registered electrical key transmitter sub-assembly.

New Key Vehicle ID Error

Although the vehicle ID stored in the certification ECU (smart key ECU assembly) should be registered to the electrical key transmitter sub-assembly during electrical key transmitter sub-assembly registration, it was not successful.

Use another unregistered electrical key transmitter sub-assembly for registration.

New Key Registration Failed

Although an unregistered electrical key transmitter sub-assembly was held near the engine switch for registration, electrical key transmitter sub-assembly registration was not successful due to wave interference (such as radio waves emitted from a device in the cabin) or a low transmitter battery.

New Key Already Registered

As a registered electrical key transmitter sub-assembly was held near the engine switch by mistake, electrical key transmitter sub-assembly registration was not successful.

Using an unregistered electrical key transmitter sub-assembly, perform the registration procedure again.

New Key ID Code Error

Replace the certification ECU (smart key ECU assembly).

New Key Information Abnormal

The ID code of an electrical key transmitter sub-assembly could not be registered to the certification ECU (smart key ECU assembly). If 2 electrical key transmitter sub-assemblies are held near the engine switch at the same time, incorrect registration information will be stored in the certification ECU (smart key ECU assembly), suspending registration.

Reregister the electrical key transmitter sub-assembly using the correct registration procedure.

Body Electrical > Smart Key > Utility

Tester Display

Operation History

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 battery before checking for DTCs.

OK:

DTCs are not output.

NG

GO TO DIAGNOSTIC TROUBLE CODE CHART

OK

2.

READ VALUE USING TECHSTREAM (UNMATCHED VEHICLE-ID)

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG)

(c) Turn the Techstream on.

(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.
Body Electrical > Smart Key > Data List

Tester Display

Unmatched Vehicle-ID

Result

Proceed to

"No" is displayed

A

"Yes" is displayed

B

B

GO TO STEP 5

A

3.

CHECK SMART KEY SYSTEM (for Start Function, Gasoline 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 engine 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

Engine Switch

*2

Electrical Key Transmitter Sub-assembly

Result

Proceed to

The power source mode changes

A

The power source mode does not change

B

B

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

A

4.

CHECK STEERING LOCK FUNCTION

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

(b) Check that the steering unlocks.

HINT:

  • When the engine 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.

NG

GO TO SMART KEY SYSTEM (for Start Function, Gasoline Model) (Unable to Unlock Steering Wheel (Engine cannot Start))

OK

5.

REGISTRATION

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

Click here

OK:

Additional registration can be completed.

OK

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

NG

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.

OK

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

NG

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 engine 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 engine 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, Gasoline 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, Gasoline 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 NO. 1 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY (FRONT FLOOR)

(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.

NG

CONNECT CONNECTORS PROPERLY

OK

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.

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

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.

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

3.

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

*a

Component with harness connected

(Certification ECU (Smart Key ECU Assembly))

*b

Waveform

*c

For 30 seconds after any door closed

*d

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:

  1. Engine switch off
  2. Electrical key transmitter sub-assembly not inside vehicle
  3. Within 30 seconds of closing any door

2 V/DIV., 500 ms/DIV.

Pulse generation

(See waveform)

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

Procedure:

  1. Engine switch off
  2. Electrical key transmitter sub-assembly not inside vehicle
  3. Within 30 seconds of closing any door

2 V/DIV., 500 ms/DIV.

Pulse generation

(See waveform)

OK

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

NG

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 engine 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 engine 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, Gasoline 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, Gasoline 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.

NG

CONNECT CONNECTORS PROPERLY

OK

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.

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

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.

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

3.

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

*a

Component with harness connected

(Certification ECU (Smart Key ECU Assembly))

*b

Waveform

*c

For 30 seconds after any door closed

*d

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:

  1. Engine switch off
  2. Electrical key transmitter sub-assembly not inside vehicle
  3. Within 30 seconds of closing any door

2 V/DIV., 500 ms/DIV.

Pulse generation

(See waveform)

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

Procedure:

  1. Engine switch off
  2. Electrical key transmitter sub-assembly not inside vehicle
  3. Within 30 seconds of closing any door

2 V/DIV., 500 ms/DIV.

Pulse generation

(See waveform)

OK

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

NG

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

Smart Key System(for Start Function, Gasoline Model)

System Voltage or GND Energization Malfunction (B228B). Short to GND in Immobiliser System Power Source Circuit (B278A). Malfunction of ID-BOX Recognition (B278D)

See More:

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Toyota Avalon (XX50) 2019-2022 Service & Repair Manual

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