Last Modified: 08-21-2023 6.11:8.1.0 Doc ID: RM100000001ARTP
Model Year Start: 2019 Model: Avalon HV Prod Date Range: [04/2018 -           ]
Title: NETWORKING: LIN COMMUNICATION SYSTEM (for HV Model): B2785; Communication Malfunction between ECUs Connected by LIN; 2019 - 2022 MY Avalon HV [04/2018 -        ]

DTC

B2785

Communication Malfunction between ECUs Connected by LIN

DESCRIPTION

If the certification ECU (smart key ECU assembly) detects a communication error with an ECU connected to the certification bus lines for 7 seconds or more, DTC B2785 will be stored.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

B2785

Communication Malfunction between ECUs Connected by LIN
  • Errors in LIN communication between ECUs or an open or short in communication lines.
  • The certification ECU (smart key ECU assembly) detects a communication error with an ECU connected to the certification bus lines for 7 seconds or more.
  • Certification ECU (smart key ECU assembly)
  • Steering lock ECU (steering lock actuator or upper bracket assembly)
  • Wire harness or connector

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • Before replacing the certification ECU (smart key ECU assembly) or steering lock ECU (steering lock actuator or upper bracket 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

  • Before performing the inspection, check that DTC B2786 or B278C is not output.

    Click here 2019 - 2022 MY Avalon HV [04/2018 -        ]; NETWORKING: LIN COMMUNICATION SYSTEM (for HV Model): DTC CHECK / CLEAR

  • 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.

CHECK STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY)

(a) Disconnect the G43 steering lock ECU (steering lock actuator or upper bracket assembly) connector.

(b) Clear the DTCs.

Body Electrical > Smart Key > Clear DTCs

(c) After 7 seconds have elapsed, check if the DTC is output.

Body Electrical > Smart Key > Trouble Codes

Result

Proceed to

DTC B2785 is output

A

DTC B2785 is not output

B
B

REPLACE STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY)

for Manual Tilt and Manual Telescopic Steering Column: Click here 2019 - 2022 MY Avalon Avalon HV [04/2018 -        ]; STEERING COLUMN: STEERING COLUMN ASSEMBLY (for Manual Tilt and Manual Telescopic Steering Column): DISASSEMBLY

for Power Tilt and Power Telescopic Steering Column: Click here 2019 - 2022 MY Avalon Avalon HV [04/2018 -        ]; STEERING COLUMN: STEERING COLUMN ASSEMBLY (for Power Tilt and Power Telescopic Steering Column): DISASSEMBLY

A

2.

CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY))

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

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

G40-13 (LIN) - Body ground

Always

10 kΩ or higher

G40-13 (LIN) - Other terminals

Always

10 kΩ or higher
OK

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

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR