PRE-CRASH SAFETY SYSTEM, Diagnostic DTC:U1104, U1104

DTC Code DTC Name
U1104 Lost Communication with Driving Support ECU
U1104 Lost Communication with Driving Support ECU

DESCRIPTION

DTC Code DTC Detection Condition Trouble Are
U1104 When the ignition switch is ON, a communication error between the millimeter wave radar sensor assembly and driving support ECU is detected for 1 second.

  • Harness or connector

  • Millimeter wave radar sensor assembly

  • Driving support ECU
U1104 When the ignition switch is ON, communication stops between the seat belt control ECU and driving support ECU for 1 second or more.

  • Seat belt control ECU

  • CAN communication system

  • Driving support ECU

WIRING DIAGRAM

A00JXI6E02

INSPECTION PROCEDURE

Note


  • When the millimeter wave radar sensor assembly is replaced with a new one, adjustment of the radar sensor beam axis must be performed Click here.

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

  • Confirm that the connector is securely connected, as a partially connected connector may be the cause of this DTC being output.

PROCEDURE


  1. CHECK FOR DTC


    1. Clear the DTCs Click here.

    2. Check for DTCs Click here.

      Result
      Result Proceed to
      DTC U1104 is not output A
      DTC U1104 is output from driving support ECU (Pre-Crash 2) B
      DTC U1104 is output from seat belt control ECU (Pre-Crash) C

    B

    CHECK HARNESS AND CONNECTOR (MILLIMETER WAVE RADAR SENSOR - BATTERY AND BODY GROUND) Click here

    C

    CHECK CAN COMMUNICATION SYSTEM Click here

    A

    USE SIMULATION METHOD TO CHECK Click here

  2. CHECK HARNESS AND CONNECTOR (MILLIMETER WAVE RADAR SENSOR - BATTERY AND BODY GROUND)


    1. A00K0LSE06
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Millimeter Wave Radar Sensor Assembly)

      Disconnect the A15 sensor connector.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A15-5 (IGB) - Body ground Ignition switch ON 11 to 14 V
      Ignition switch off Below 1 V

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A15-2 (SGND) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK HARNESS AND CONNECTOR (DRIVING SUPPORT ECU - BODY GROUND)


    1. A00K0G9E05
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Driving Support ECU)

      Disconnect the G119 ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G119-25 (GND) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (MILLIMETER WAVE RADAR SENSOR - DRIVING SUPPORT ECU)


    1. Disconnect the A15 sensor connector.

    2. Disconnect the G119 ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A15-4 (LRRD) - G119-38 (LRRD) Always Below 1 Ω
      A15-4 (LRRD) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. REPLACE DRIVING SUPPORT ECU


    1. Replace the driving support ECU Click here.


    NEXT

  6. CHECK FOR DTC


    1. Clear the DTCs Click here.

    2. Check for DTCs Click here.

      OK
      DTC U1104 is not output.

    NG

    REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY Click here

    OK

    END (DRIVING SUPPORT ECU IS DEFECTIVE)

  7. CHECK CAN COMMUNICATION SYSTEM


    1. Select "Bus Check" from the "System Select" screen on the intelligent tester.

    2. Select "Communication Malfunction DTC" from the "Bus Check" screen, and then select "Enter".

      Result
      Result Proceed to
      CAN DTC is not output A
      CAN DTC is output (for LHD with Entry and Start System) B
      CAN DTC is output (for LHD without Entry and Start System) C
      CAN DTC is output (for RHD with Entry and Start System) D
      CAN DTC is output (for RHD without Entry and Start System) E

    B

    GO TO CAN COMMUNICATION SYSTEM Click here

    C

    GO TO CAN COMMUNICATION SYSTEM Click here

    D

    GO TO CAN COMMUNICATION SYSTEM Click here

    E

    GO TO CAN COMMUNICATION SYSTEM Click here

    A

    USE SIMULATION METHOD TO CHECK Click here