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PRE-COLLISION SYSTEM(for Mono Camera Type), Diagnostic DTC:U1104

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

The driving support ECU assembly is connected to the millimeter wave radar sensor assembly, forward recognition camera and skid control ECU assembly via CAN communication. If communication with the millimeter wave radar sensor assembly, forward recognition camera or skid control ECU assembly stops, the driving support ECU assembly stores DTC U1104.

DTC No. Detection Item DTC Detection Condition Trouble Area
U1104 Lost Communication with Driving Support ECU

Any of the following conditions is met:


  • When the power switch is on (IG), a communication error between the driving support ECU assembly and the millimeter wave radar sensor assembly is detected for approximately 0.2 seconds or more.

  • When the power switch is on (IG), a communication error between the driving support ECU assembly and the forward recognition camera is detected for approximately 0.3 seconds or more.

  • When the power switch is on (IG), a communication error between the driving support ECU assembly and the skid control ECU assembly is detected for approximately 1.5 seconds or more.

  • CAN communication system

  • Electronically controlled brake system

  • Front camera system

  • Millimeter wave radar sensor assembly

  • Forward recognition camera

  • Driving support ECU assembly
Table 1. DTC Detection Conditions:
  Vehicle Condition
Pattern 1 Pattern 2 Pattern 3
Diagnosis Condition power switch is on (IG) ○ ○ ○
Malfunction Status A communication error between the driving support ECU assembly and the millimeter wave radar sensor assembly is detected ○ - -
A communication error between the driving support ECU assembly and the forward recognition camera is detected - ○ -
A communication error between the driving support ECU assembly and the skid control ECU assembly is detected - - ○
Detection Time Approximately 0.2 seconds or more Approximately 0.3 seconds or more Approximately 1.5 seconds or more
Number of Trips 1 trip 1 trip 1 trip
Tip:

DTC will be output when conditions for either of the patterns in the table above are met.

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CAUTION / NOTICE / HINT

Note:

  • When replacing the driving support ECU assembly, always replace it with a new one. If a driving support ECU assembly which was installed to another vehicle is used, the information stored in the driving support ECU assembly will not match the information from the vehicle. As a result, a DTC may be stored.

  • 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 Learning.

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  • When replacing the millimeter wave radar sensor assembly, always replace it with a new one. If a millimeter wave radar sensor assembly which was installed to another vehicle is used, the information stored in the millimeter wave radar sensor assembly will not match the information from the vehicle. As a result, a DTC may be stored.

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

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  • Confirm that the connectors are securely connected, as a partially connected connector can cause this DTC to be stored.

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PROCEDURE


  1. Click here

    CHECK FOR DTCs (FRONT CAMERA SYSTEM)


    1. Check for DTCs.

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      1. Chassis > Front Recognition Camera > Trouble Codes


      Result
      Result Proceed to
      DTCs are not output A
      DTC U0235 is output B
      DTC U0235 and U1104 are output C
      DTC U1104 is output D

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    READ VALUE USING GTS (CAN BUS CHECK)


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: System Select / Can Bus Check.

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      1. CAN Bus Check

      Result
      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

  3. Click here

    CHECK FOR DTCs (ELECTRONICALLY CONTROLLED BRAKE SYSTEM)


    1. Check for DTCs.

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      1. Chassis > ABS/VSC/TRC > Trouble Codes


      Tip:

      Pre-collision system DTC U1104 may be stored due to a malfunction in the electronically controlled brake system. Therefore it is necessary to check for and troubleshoot electronically controlled brake system DTCs first.

      Result
      Result Proceed to
      Electronically controlled brake system DTC are not output A
      Electronically controlled brake system DTC are output B

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    TEST MODE INSPECTION (ELECTRONICALLY CONTROLLED BRAKE SYSTEM)

    Tip:

    When entering test mode, the skid control ECU assembly communicates with the driving support ECU assembly to judge whether the vehicle is equipped with the pre-collision system. Therefore, do not exit test mode within 5 seconds of entering test mode.


    1. Procedure to Enter Test Mode (Signal Check)


      1. Turn the power switch on (IG).

      2. Change the shift state to park (P).

      3. Check that the steering wheel is centered.

      4. Turn the power switch off.

      5. Connect the GTS to the DLC3.

      6. Turn the power switch on (IG).

      7. Check that the parking brake is released.

      8. Turn the GTS on.

      9. Switch the skid control ECU assembly to Test Mode (Signal Check) using the GTS.

      10. Enter the following menus: Chassis / ABS/VSC/TRC / Utility / Signal Check.

        Tip:

        Do not exit test mode within 5 seconds of entering test mode. If test mode is exited within 5 seconds of entering test mode, DTC U1104 may be stored. If DTC U1104 is output after exiting test mode, enter test mode again, wait at least 5 seconds, then recheck for DTCs.


        1. Chassis > ABS/VSC/TRC > Utility
          Tester Display
          Signal Check




    2. Test Mode (Signal Check) Display Check


      1. Check that the ABS warning, brake warning / yellow (minor malfunction) and slip indicator lights come on for several seconds and then blink in the Test Mode pattern.

        Tip:

        If the ABS warning light, brake warning light / yellow (minor malfunction) or slip indicator light remains illuminated or does not illuminate when Test Mode (Signal Check) is entered, a component or wire harness may be malfunctioning.

    3. End of Test Mode (Signal Check)


      1. Turn the power switch off and disconnect the GTS.

      Result
      Proceed to
      NEXT

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    CHECK FOR DTCs (PRE-COLLISION SYSTEM)


    1. Clear the DTCs.

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      1. Body Electrical > Pre-Collision 2 > Clear DTCs


    2. Make sure that the DTC detection conditions are met.

      Tip:

      If the detection conditions are not met, the system cannot detect the malfunction.

    3. Check for DTCs.

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      1. Body Electrical > Pre-Collision 2 > Trouble Codes


      Result
      Result Proceed to
      DTC U1104 is not output A
      DTC U1104 is output B

    • A

      END

    • B

      REPLACE DRIVING SUPPORT ECU ASSEMBLYClick here

  6. Click here

    REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY


    1. Replace the millimeter wave radar sensor assembly.

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    2. Perform millimeter wave radar sensor assembly adjustment.

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      Result
      Proceed to
      NEXT

    • NEXT

      END

  7. Click here

    REPLACE FORWARD RECOGNITION CAMERA


    1. Replace the forward recognition camera.

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    2. Perform Forward Recognition Camera Learning.

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      Result
      Proceed to
      NEXT

    • NEXT

      END