Last Modified: 04-05-2023 6.11:8.1.0 Doc ID: RM1000000018DN9
Model Year Start: 2018 Model: Sienna Prod Date Range: [11/2017 -           ]
Title: NETWORKING: CAN COMMUNICATION SYSTEM: Open in One Side of Bus 2 Branch Line; 2018 - 2020 MY Sienna [11/2017 -        ]

Open in One Side of Bus 2 Branch Line

DESCRIPTION

If an ECU or sensor is not displayed on the CAN Bus Check screen of the Techstream and some ECUs and sensors repeatedly appear and disappear from the screen when the CAN main bus wires are normal (there is no open, short, short to +B or short to GND in the main bus wires), there may be an open circuit in either of the wires in a CAN branch.

HINT:

If some ECUs and sensors repeatedly appear and disappear from the CAN Bus Check screen, communication between the normal ECUs (sensors) and the Techstream may be affected by the incomplete signals that are output from the ECU that has an open circuit in either of the wires in its CAN branch. In this case, the CAN branch wires for the ECUs and sensors that repeatedly appear and disappear from the screen are normal and the ECU that is not displayed on the screen may be the main cause of the problem (this ECU may have an open circuit in either of the wires in its CAN branch).

Detection Item

Trouble Area

2 or more ECUs and/or sensors do not appear on the Techstream CAN Bus Check screen.

One side of CAN branch wire is open, or output signals are incomplete.

  • 4WD control ECU*1
  • Airbag sensor assembly
  • Air conditioning amplifier assembly
  • Central gateway ECU (network gateway ECU)
  • Main body ECU (multiplex network body ECU)
  • Brake actuator assembly (skid control ECU)
  • Certification ECU (smart key ECU assembly)*2
  • Power management control ECU*2
  • Steering column assembly (power steering ECU)
  • Steering angle sensor (spiral cable with sensor sub-assembly)
  • *1: for AWD
  • *2: w/ Smart Key System

CAUTION / NOTICE / HINT

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

NOTICE:

  • Because the order of diagnosis is important to allow correct diagnosis, make sure to begin troubleshooting using How to Proceed with Troubleshooting when CAN communication system related DTCs are output.

    Click here 2018 - 2020 MY Sienna [11/2017 -        ]; NETWORKING: CAN COMMUNICATION SYSTEM: HOW TO PROCEED WITH TROUBLESHOOTING

  • Before measuring the resistance of the CAN bus, turn the ignition switch off and leave the vehicle for 1 minute or more without operating the key or any switches, or opening or closing the doors. After that, disconnect the cable from the negative (-) battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.
  • After turning the ignition switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work.

    Click here 2017 - 2020 MY Sienna [08/2016 -        ]; INTRODUCTION: REPAIR INSTRUCTION: PRECAUTION

  • Some parts must be initialized and set when replacing or removing and installing parts.

    Click here 2018 - 2020 MY Sienna [11/2017 -        ]; INTRODUCTION: REPAIR INSTRUCTION: INITIALIZATION

  • After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.

    DTC check procedure: Turn the ignition switch to ON and wait for 1 minute or more. Then operate the suspected malfunctioning system and drive the vehicle at 60 km/h (37 mph) or more for 5 minutes or more.

  • After the repair, perform the CAN bus check and check that all the ECUs and sensors connected to the CAN communication system are displayed as normal.

    Click here 2018 MY Sienna [11/2017 - 08/2018]; NETWORKING: CAN COMMUNICATION SYSTEM: DIAGNOSIS SYSTEM 2019 - 2020 MY Sienna [08/2018 -        ]; NETWORKING: CAN COMMUNICATION SYSTEM: DIAGNOSIS SYSTEM

  • Before replacing the ECM, power management control ECU, main body ECU (multiplex network body ECU) or certification ECU (smart key ECU assembly), refer to Registration.

    Click here 2017 - 2020 MY Sienna [08/2016 -        ]; THEFT DETERRENT / KEYLESS ENTRY: ENGINE IMMOBILISER SYSTEM(w/ Smart Key System): REGISTRATION

HINT:

  • Before disconnecting related connectors for inspection, push in on each connector body to check that the connector is not loose or disconnected.
  • When a connector is disconnected, check that the terminals and connector body are not cracked, deformed or corroded.

PROCEDURE

1.

CHECK FOR OPEN IN ONE SIDE OF BUS 2 CAN BRANCH WIRE

(a) Based on the vehicle equipment and specifications, confirm the systems that use CAN communication (See page 2018 MY Sienna [11/2017 - 08/2018]; NETWORKING: CAN COMMUNICATION SYSTEM: DIAGNOSIS SYSTEM 2019 - 2020 MY Sienna [08/2018 -        ]; NETWORKING: CAN COMMUNICATION SYSTEM: DIAGNOSIS SYSTEM ).

(b) Using the Techstream, select and perform the CAN bus check (See page 2018 - 2020 MY Sienna [11/2017 -        ]; NETWORKING: CAN COMMUNICATION SYSTEM: HOW TO PROCEED WITH TROUBLESHOOTING ).

(c) Observe the screen for approximately 2 minutes to check the ECUs and sensors that are not displayed on the screen and also those that repeatedly appear and disappear from the screen.

(d) Check the applicable communication stop mode for the ECU or sensor that is not displayed on the screen.

NEXT

GO TO CORRESPONDING COMMUNICATION STOP MODE

(See page 2018 MY Sienna [11/2017 - 08/2018]; NETWORKING: CAN COMMUNICATION SYSTEM: PROBLEM SYMPTOMS TABLE 2019 - 2020 MY Sienna [08/2018 -        ]; NETWORKING: CAN COMMUNICATION SYSTEM: PROBLEM SYMPTOMS TABLE )