Last Modified: 08-21-2023 6.11:8.1.0 Doc ID: RM100000001B2OE
Model Year Start: 2019 Model: Avalon HV Prod Date Range: [04/2018 -           ]
Title: THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, HV Model): B278D; Malfunction of ID-BOX Recognition; 2019 - 2022 MY Avalon HV [04/2018 -        ]

DTC

B278D

Malfunction of ID-BOX Recognition

DESCRIPTION

When the certification ECU (smart key ECU assembly) detects an input signal indicating that the vehicle is equipped with an ID code box even though the ID code box is not registered, the certification ECU (smart key ECU assembly) stores this DTC.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Note

B278D

Malfunction of ID-BOX Recognition

One of the following conditions is met:

  • The certification ECU (smart key ECU assembly) recognizes that the wire harness judging whether the vehicle is equipped with an ID code box or not is provided even though the ID code box is not registered.
  • The certification ECU (smart key ECU assembly) receives a LIN signal from the ID code box even though the ID code box is not registered.
  • The certification ECU (smart key ECU assembly) receives a LIN signal from the ID code box even though the wire harness judging whether the vehicle is equipped with an ID code box or not is not provided.

Misconnection of the ID code box

DTC output confirmation operation:

  • Always

Vehicle Condition and Fail-safe Operation when Malfunction Detected

Vehicle Condition when Malfunction Detected

Fail-safe Operation when Malfunction Detected

Key registration will be prohibited

-

Related Data List and Active Test

DTC No.

Data List and Active Test

B278D

-

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 2019 - 2022 MY Avalon HV [04/2018 -        ]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, HV Model): HOW TO PROCEED WITH TROUBLESHOOTING

  • Before performing following procedure, check that the ID code box (immobiliser code ECU) is not installed on the vehicle.
  • Before replacing the certification ECU (smart key ECU assembly), refer to Registration.

    Click here 2019 - 2020 MY Avalon HV [04/2018 - 08/2020]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, HV Model): REGISTRATION 2021 - 2022 MY Avalon HV [08/2020 -        ]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, HV Model): REGISTRATION

  • After repair, confirm that no DTCs are output by performing "DTC Output Confirmation Operation."

PROCEDURE

1.

CLEAR DTC

(a) Clear the DTCs.

Body Electrical > Smart Key > Clear DTCs

NEXT

2.

CHECK DTC OUTPUT

(a) Check for DTCs.

Body Electrical > Smart Key > Trouble Codes

HINT:

Before checking for DTCs, perform the "DTC Output Confirmation Operation" procedure.

OK:

DTC B278D is not output.

OK

END
NG

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) 2019 - 2021 MY Avalon Avalon HV [04/2018 - 08/2021]; THEFT DETERRENT / KEYLESS ENTRY: CERTIFICATION ECU: REMOVAL 2022 MY Avalon Avalon HV [08/2021 -        ]; THEFT DETERRENT / KEYLESS ENTRY: CERTIFICATION ECU: REMOVAL