Toyota Venza Quiz
Networking

Communication Malfunction between ECUs Connected by LIN (B2785)

In this manual: Networking
Introduction — 15Maintenance — 8Audio / Video — 102Garage Door Opener — 8Navigation / Multi Info Display — 81Park Assist / Monitoring — 50Brake (front) — 7Brake (rear) — 7Brake Control / Dynamic Control Systems — 79Brake System (other) — 28Parking Brake — 22Axle And Differential — 44Drive Shaft / Propeller Shaft — 24Mf1a Transfer / 4wd / Awd — 46U660e Automatic Transmission / Transaxle — 1241ar-fe Cooling — 311ar-fe Emission Control — 101ar-fe Engine Control — 1331ar-fe Engine Mechanical — 441ar-fe Fuel — 311ar-fe Intake / Exhaust — 211ar-fe Lubrication — 111ar-fe Starting — 16Cruise Control — 241ar-fe Battery / Charging — 162gr-fe Battery / Charging — 17Networking — 67Power Distribution — 8Power Assist Systems — 34Steering Column — 37Steering Gear / Linkage — 29Alignment / Handling Diagnosis — 4Front Suspension — 39Rear Suspension — 35Tire / Wheel — 4Tire Pressure Monitoring — 35Door / Hatch — 83Exterior Panels / Trim — 56Horn — 4Lighting (ext) — 89Mirror (ext) — 36Sliding Roof / Convertible — 26Window / Glass — 87Wiper / Washer — 30Door Lock — 85Heating / Air Conditioning — 82Interior Panels / Trim — 20Lighting (int) — 37Meter / Gauge / Display — 41Mirror (int) — 9Power Outlets (int) — 10Seat — 84Seat Belt — 43Supplemental Restraint Systems — 131Theft Deterrent / Keyless Entry — 155
~2min read
DESCRIPTION

This DTC is stored when LIN communication from the certification ECU stops for a certain amount of time.

DTC No.

DTC Detection Condition

Trouble Area

B2785
  • Errors in LIN communication between the ECUs or an open or short in communication lines.
  • LIN communication from the certification ECU (smart key ECU assembly) stops for a certain amount of time or more.
  • Certification ECU (Smart key ECU assembly)
  • Power source control ECU (Power management control computer assembly)
  • Steering lock ECU (Steering lock actuator assembly)
  • Wire harness or connector
WIRING DIAGRAM
CAUTION / NOTICE / HINT

NOTICE:

  • If the certification ECU (smart key ECU assembly) is replaced, register the key.
  • If the steering lock ECU (steering lock actuator assembly) is replaced, register the ECU code.
  • When using the Techstream to troubleshoot with the ignition switch off:

    Connect the Techstream to the DLC3, and turn the 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 - EACH ECU)

(a) Disconnect the D25, D43 and D17 ECU connectors.

Text in Illustration

*1

Front view of wire harness connector

(to Certification ECU (Smart Key ECU Assembly))

*2

Front view of wire harness connector

(to Power Management Control ECU)

*3

Front view of wire harness connector

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

-

-

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

D25-29 (LIN) - D17-5 (LIN)

Always

Below 1 Ω

D25-29 (LIN) - D43-24 (LIN2)

Always

Below 1 Ω

D25-29 (LIN) - Body ground

Always

10 kΩ or higher

Standard Voltage:

Tester Connection

Condition

Specified Condition

D25-29 (LIN) - Body ground

Always

Below 1 V

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

  1. CHECK DTC OUTPUT (STEERING LOCK ECU (STEERING LOCK ACTUATOR ASSEMBLY))

(a) Reconnect the D25 and D43 ECU connectors.

(b) Clear the DTC (See page ).


(c) Recheck for DTCs.

Result

Proceed to

DTC B2785 is output

A

DTC B2785 is not output

B

B

REPLACE STEERING LOCK ECU (STEERING LOCK ACTUATOR ASSEMBLY)
A

  1. CHECK DTC OUTPUT (POWER MANAGEMENT CONTROL ECU)

(a) Reconnect the D17 ECU connector.

(b) Disconnect the D43 ECU connector.

(c) Clear the DTC (See page ).


(d) Recheck for DTCs.

Result

Proceed to

DTC B2785 is output

A

DTC B2785 is not output

B

A

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

B

REPLACE POWER MANAGEMENT CONTROL ECU

Test yourself

A quick Toyota Venza quiz: every answer comes with an explanation and a link to the manual page.