Last Modified: 08-21-2023 6.11:8.1.0 Doc ID: RM100000001ARTV
Model Year Start: 2019 Model: Avalon HV Prod Date Range: [04/2018 -           ]
Title: NETWORKING: LIN COMMUNICATION SYSTEM (for HV Model): B278C; Lost Communication with Power Source Control; 2019 - 2022 MY Avalon HV [04/2018 -        ]

DTC

B278C

Lost Communication with Power Source Control

DESCRIPTION

When an internal malfunction is detected in the certification ECU (smart key ECU assembly), this DTC is stored.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

B278C

Lost Communication with Power Source Control

An internal malfunction occurs in the certification ECU (smart key ECU assembly).

Certification ECU (smart key ECU assembly)

CAUTION / NOTICE / HINT

NOTICE:

  • 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

  • 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 Model Code "KEY REGIST" 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.

PROCEDURE

1.

CLEAR DTC

(a) Clear the DTCs.

Body Electrical > Smart Key > Clear DTCs

NEXT

2.

CHECK FOR DTC

(a) Check for DTCs.

Body Electrical > Smart Key > Trouble Codes

OK:

DTC B278C is not output.

OK

USE SIMULATION METHOD TO CHECK

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