Last Modified: 04-05-2023 6.11:8.1.0 Doc ID: RM1000000018H9U
Model Year Start: 2018 Model: Sienna Prod Date Range: [11/2017 - 08/2018]
Title: NETWORKING: CAN COMMUNICATION SYSTEM: Millimeter Wave Radar Sensor Communication Stop Mode; 2018 MY Sienna [11/2017 - 08/2018]

Millimeter Wave Radar Sensor Communication Stop Mode

DESCRIPTION

Detection Item

Symptom

Trouble Area

Millimeter Wave Radar Sensor Communication Stop Mode

Either Condition is met:

  • Communication stop for "Front Radar" 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

  • Communication system DTCs (DTCs that start with U) that correspond to "Millimeter Wave Radar Sensor 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

  • Millimeter wave radar sensor assembly branch wire or connector
  • Power source circuit of millimeter wave radar sensor assembly
  • Millimeter wave radar sensor assembly ground circuit
  • Millimeter wave radar sensor assembly

HINT:

For vehicle with pre-collision system 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 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

  • 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 FOR OPEN IN CAN BUS WIRE (MILLIMETER WAVE RADAR SENSOR ASSEMBLY BRANCH WIRE)

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

(b) Disconnect the millimeter wave radar sensor assembly connector.

*a

Front view of wire harness connector

(to Millimeter Wave Radar Sensor Assembly)

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A77-3 (CA2H) - A77-2 (CA2L)

Cable disconnected from negative (-) battery terminal

54 to 69 Ω
NG

REPAIR OR REPLACE CAN BRANCH WIRE OR CONNECTOR
OK

2.

CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)

(a) Disconnect the millimeter wave radar sensor assembly connector.

*a

Front view of wire harness connector

(to Millimeter Wave Radar Sensor Assembly)

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A77-1 (SGND) - 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.

Click here 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

A77-8 (IGB) - Body ground

Ignition switch ON

11 to 14 V

Ignition switch off

Below 1 V
OK

REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR