Last Modified: 04-05-2023 6.11:8.1.0 Doc ID: RM1000000018DLM
Model Year Start: 2018 Model: Sienna Prod Date Range: [11/2017 -           ]
Title: NETWORKING: CAN COMMUNICATION SYSTEM: 4WD Control ECU Communication Stop Mode; 2018 - 2020 MY Sienna [11/2017 -        ]

4WD Control ECU Communication Stop Mode

DESCRIPTION

Detection Item

Symptom

Trouble Area

4WD Control ECU Communication Stop Mode

Either condition is met:

  • Communication stop for "Four Wheel Drive Control" is indicated on the "Communication Bus Check" screen of the Techstream.

    Click here 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

  • Communication system DTCs (DTCs that start with U) that correspond to "4WD Control ECU Communication Stop Mode" in "DTC Combination Table" are output.

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

  • Power source or inside 4WD ECU assembly
  • 4WD ECU assembly ground circuit
  • 4WD ECU assembly branch wire and connector
  • 4WD ECU assembly

HINT:

For AWD only.

WIRING DIAGRAM

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 engine 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

  • Inspect the fuses for circuits related to this system before performing the following procedure.

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 CAN BUS LINE FOR DISCONNECTION (4WD ECU ASSEMBLY BRANCH WIRE)

(a) Disconnect the cable from the negative (-) battery terminal.

(b) Disconnect the 4WD ECU assembly connector.

*a

Front view of wire harness connector

(to 4WD ECU Assembly)

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

K1-14 (CANH) - K1-16 (CANL)

Cable disconnected from negative (-) battery terminal

54 to 69 Ω
NG

REPAIR OR REPLACE CAN BRANCH WIRE CONNECTED TO 4WD ECU ASSEMBLY
OK

2.

CHECK WIRE HARNESS (4WD ECU ASSEMBLY - POWER SOURCE)

(a) Disconnect the 4WD ECU assembly connector.

*a

Front view of wire harness connector

(to 4WD ECU Assembly)

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

K1-23 (GND) - Body ground

Cable disconnected from negative (-) battery terminal

Below 1 Ω

(c) Reconnect the cable to the negative (-) battery terminal.

NOTICE:

When disconnecting the cable, some systems need to be initialized after the cable is reconnected (See page 2018 - 2020 MY Sienna [11/2017 -        ]; INTRODUCTION: REPAIR INSTRUCTION: INITIALIZATION )

(d) Measure the voltage according to the value(s) in the table below

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

K1-9 (BSLC) - Body ground

Always

11 to 14 V

K1-11 (IG1) - Body ground

Ignition switch ON

11 to 14 V
OK

REPLACE 4WD ECU ASSEMBLY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR