Last Modified: 04-05-2023 6.11:8.1.0 Doc ID: RM100000000VJEZ
Model Year Start: 2016 Model: Sienna Prod Date Range: [12/2015 -           ]
Title: NETWORKING: LIN COMMUNICATION SYSTEM: B2785; Communication Malfunction between ECUs Connected by LIN; 2016 - 2020 MY Sienna [12/2015 -        ]

DTC

B2785

Communication Malfunction between ECUs Connected by LIN

DESCRIPTION

The certification ECU (smart key ECU) intermittently monitors the LIN communication bus between the components related to certification. DTC B2785 is stored when a malfunction in the LIN communication bus between the components related to certification is detected continuously 3 times.

DTC Code

DTC Detection Condition

Trouble Area

B2785

The certification ECU (smart key ECU) detects a malfunction in the LIN communication bus between components related to certification continuously 3 times.

  • Certification ECU (smart key ECU)
  • Steering lock actuator assembly (steering lock ECU)
  • Harness and connector
  • Power management control ECU

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

When using the Techstream with the ignition switch off to troubleshoot:

Connect Techstream to the vehicle, and turn a courtesy switch on and off at 1.5 second intervals until communication between the Techstream and vehicle begins.

PROCEDURE

1.

CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU) - EACH ECU)

Text in Illustration

*a

Component without harness connected

(Instrument Panel Junction Block Assembly)

*b

Front view of wire harness connector

(to Steering Lock Actuator Assembly (Steering lock ECU))

*c

Front view of wire harness connector

(to Power Management Control ECU)

-

-

(a) Disconnect the D88 certification ECU (smart key ECU) connector.

(b) Disconnect the D29 steering lock actuator assembly (steering lock ECU) connector.

(c) Disconnect the D89 power management control ECU connector.

(d) Measure the resistance and voltage according to the value(s) in the tables below.

Standard Resistance (Check for Open):

Tester Connection

Condition

Specified Condition

D88-29 (LIN) - D29-5 (LIN)

Always

Below 1 Ω

D88-29 (LIN) - D89-24 (LIN2)

Always

Below 1 Ω

Standard Resistance (Check for Short):

Tester Connection

Condition

Specified Condition

D88-29 (LIN) - Body ground

Always

10 kΩ or higher

Standard Voltage:

Tester Connection

Condition

Specified Condition

D88-29 (LIN) - Body ground

Always

Below 0.5 V

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

2.

CHECK FOR DTC

(a) Clear the DTC (See page 2016 - 2020 MY Sienna [12/2015 -        ]; NETWORKING: LIN COMMUNICATION SYSTEM: DTC CHECK / CLEAR ).

(b) Reconnect the D88 certification ECU (smart key ECU) and D89 steering lock actuator assembly (steering lock ECU) connectors.

(c) Check for DTCs.

Result

Result

Proceed to

DTC B2785 is output

A

DTC B2785 is not output

B

B

GO TO STEP 4

A

3.

CHECK FOR DTC

(a) Clear the DTC (See page 2016 - 2020 MY Sienna [12/2015 -        ]; NETWORKING: LIN COMMUNICATION SYSTEM: DTC CHECK / CLEAR ).

(b) Reconnect the D89 power management control ECU connector.

(c) Disconnect the D29 steering lock actuator assembly (steering lock ECU) connector.

(d) Check for DTCs.

Result

Result

Proceed to

DTC B2785 is output

A

DTC B2785 is not output

B

A

REPLACE CERTIFICATION ECU (SMART KEY ECU)

(See page 2016 - 2017 MY Sienna [12/2015 - 11/2017]; THEFT DETERRENT / KEYLESS ENTRY: CERTIFICATION ECU: REMOVAL 2018 - 2020 MY Sienna [11/2017 -        ]; THEFT DETERRENT / KEYLESS ENTRY: CERTIFICATION ECU: REMOVAL )

B

GO TO STEP 6

4.

REPLACE POWER MANAGEMENT CONTROL ECU

(a) Temporarily replace the power management control ECU with a new or normally functioning one.

(b) Clear the DTC (See page 2016 - 2020 MY Sienna [12/2015 -        ]; NETWORKING: LIN COMMUNICATION SYSTEM: DTC CHECK / CLEAR ).

NEXT

5.

CHECK FOR DTC

(a) Check for DTCs (See page 2016 - 2020 MY Sienna [12/2015 -        ]; NETWORKING: LIN COMMUNICATION SYSTEM: DTC CHECK / CLEAR ).

Result

Result

Proceed to

DTC B2785 is not output

A

DTC B2785 is output

B

A

END (POWER MANAGEMENT CONTROL ECU IS MALFUNCTIONING)

B

REPLACE CERTIFICATION ECU (SMART KEY ECU)

(See page 2016 - 2017 MY Sienna [12/2015 - 11/2017]; THEFT DETERRENT / KEYLESS ENTRY: CERTIFICATION ECU: REMOVAL 2018 - 2020 MY Sienna [11/2017 -        ]; THEFT DETERRENT / KEYLESS ENTRY: CERTIFICATION ECU: REMOVAL )

6.

REPLACE STEERING LOCK ACTUATOR ASSEMBLY (STEERING LOCK ECU)

(a) Temporarily replace the steering lock actuator assembly (steering lock ECU) with a new or normally functioning one (See page 2016 - 2020 MY Sienna [12/2015 -        ]; STEERING COLUMN: STEERING COLUMN ASSEMBLY: REMOVAL ).

(b) Clear the DTC (See page 2016 - 2020 MY Sienna [12/2015 -        ]; NETWORKING: LIN COMMUNICATION SYSTEM: DTC CHECK / CLEAR ).

NEXT

7.

CHECK FOR DTC

(a) Check for DTCs (See page 2016 - 2020 MY Sienna [12/2015 -        ]; NETWORKING: LIN COMMUNICATION SYSTEM: DTC CHECK / CLEAR ).

Result

Result

Proceed to

DTC B2785 is not output

A

DTC B2785 is output

B

A

END (STEERING LOCK ACTUATOR ASSEMBLY IS MALFUNCTIONING)

B

REPLACE CERTIFICATION ECU (SMART KEY ECU)

(See page 2016 - 2017 MY Sienna [12/2015 - 11/2017]; THEFT DETERRENT / KEYLESS ENTRY: CERTIFICATION ECU: REMOVAL 2018 - 2020 MY Sienna [11/2017 -        ]; THEFT DETERRENT / KEYLESS ENTRY: CERTIFICATION ECU: REMOVAL )