Last Modified: 04-05-2023 6.11:8.1.0 Doc ID: RM1000000018YBU
Model Year Start: 2018 Model: Sienna Prod Date Range: [11/2017 -           ]
Title: PRE-COLLISION: PRE-COLLISION SYSTEM: U023A; Lost Communication with Front Camera Module; 2018 - 2020 MY Sienna [11/2017 -        ]

DTC

U023A

Lost Communication with Front Camera Module

DESCRIPTION

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

U023A

Lost Communication with Front Camera Module

When the ignition switch is ON, a communication error between the forward recognition camera and driving support ECU is detected for approximately 3 seconds.
  • Forward recognition camera branch line or connector
  • Forward recognition camera power source circuit
  • Forward recognition camera

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • w/ Stop and Start System:

    As the forward recognition camera is supplied power from the engine stop and start ECU, make sure that the stop and start system is not malfunctioning before performing the following inspection procedure.

  • w/o Stop and Start System:

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

  • 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

  • When replacing the forward recognition camera, always replace it with a new one. If a forward recognition camera which was installed to another vehicle is used, the information stored in the forward recognition camera will not match the information from the vehicle. As a result, a DTC may be stored.
  • If the forward recognition camera has been replaced with a new one, be sure to perform forward recognition camera adjustment.

    Click here 2018 - 2020 MY Sienna [11/2017 -        ]; CRUISE CONTROL: FRONT CAMERA: ADJUSTMENT (SEQUENTIAL RECOGNITION)

HINT:

  • Operating the ignition switch, any other switches or a door triggers related ECU and sensor communication on the CAN. This communication will cause the resistance value to change.
  • Even after DTCs are cleared, if a DTC is stored again after driving the vehicle for a while, the malfunction may be occurring due to vibration of the vehicle. In such a case, wiggling the connectors of ECUs or wire harnesses while performing the inspection below may help determine the cause of the malfunction.

PROCEDURE

1.

READ VALUE USING TECHSTREAM (CAN BUS CHECK)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: System Select / CAN Bus Check.

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

Result

Proceed to

All of the ECUs and sensors that are currently connected to the CAN communication system are displayed

A

None of the ECUs and sensors that are currently connected to the CAN communication system are displayed, or some of them are not displayed

B
B

GO TO CAN COMMUNICATION SYSTEM

A

2.

CHECK FOR DTCs (PRE-COLLISION SYSTEM)

(a) Clear the DTCs.

Click here 2018 - 2020 MY Sienna [11/2017 -        ]; PRE-COLLISION: PRE-COLLISION SYSTEM: DTC CHECK / CLEAR

(b) Perform the following procedure.

HINT:

If the following procedure is not performed, the previously output DTC cannot be detected.

  1. Turn the ignition switch to ON and wait 2 seconds or more.

(c) Check for DTCs.

Click here 2018 - 2020 MY Sienna [11/2017 -        ]; PRE-COLLISION: PRE-COLLISION SYSTEM: DTC CHECK / CLEAR

Result

Proceed to

DTC U1002 is not output

A

DTC U1002 is output

B
B

GO TO DTC CHART (U1002)

A

3.

CHECK FOR OPEN IN CAN BUS MAIN LINES (FORWARD RECOGNITION CAMERA)

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

(b) Disconnect the forward recognition camera connector.

*a

Front view of wire harness connector

(to Forward Recognition Camera)

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

T32-6 (CANH) - T32-12 (CANL)

Cable disconnected from negative (-) battery terminal

108 to 132 Ω

(d) Connect the forward recognition camera connector.

NG

REPAIR OR REPLACE CAN BUS MAIN LINE OR CONNECTOR (NO. 5 CAN JUNCTION CONNECTOR - FORWARD RECOGNITION CAMERA)
OK

4.

CHECK HARNESS AND CONNECTOR (POWER SOURCE VOLTAGE)

(a) Disconnect the forward recognition camera connector.

*a

Front view of wire harness connector

(to Forward Recognition Camera)

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

T32-10 (GND) - Body ground

Always

Below 1 Ω

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

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

T32-7 (IGB) - Body ground

Ignition switch ON

11 to 14 V

(e) Connect the forward recognition camera connector.

OK

REPLACE FORWARD RECOGNITION CAMERA

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)