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DTC U1104: Lost Communication with Driving Support ECU [09/2017 - 05/2019]: Procedure

  1. CHECK FOR DTCs (PRE-COLLISION SYSTEM) 
    1. Check for DTCs.

      Refer to DTC CHECK / CLEAR [09/2017 - 05/2019]

      Body Electrical > Pre-Collision 2 > Trouble Codes 

      Result

      Result Proceed to
      DTC U1104 and other DTCs are output A
      Only DTC U1104 is output B

    Result: 

    A 

    GO TO DIAGNOSTIC TROUBLE CODE CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART [09/2017 - 05/2019] 

    Result: 

    B 

    See step  2

  2. CHECK FOR DTCs (FORWARD RECOGNITION CAMERA SYSTEM) 
    1. Check for DTCs.

      Refer to DTC CHECK / CLEAR [09/2017 - 05/2019]

      Chassis > Front Recognition Camera > Trouble Codes 

      Result

      Result Proceed to
      Forward recognition camera system DTCs are not output A
      Forward recognition camera system DTCs are output B

    Result: 

    B 

    GO TO FORWARD RECOGNITION CAMERA SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2017 - 05/2019] 

    Result: 

    A 

    See step  3

  3. CHECK FOR DTCs (VEHICLE STABILITY CONTROL SYSTEM) 
    1. Check for DTCs.

      Refer to DTC CHECK / CLEAR [10/2014 - 05/2019]

      Chassis > ABS/VSC/TRAC > Trouble Codes 

      Result

      Result Proceed to
      Vehicle stability control system DTC are not output A
      Vehicle stability control system DTC are output B

    Result: 

    B 

    GO TO VEHICLE STABILITY CONTROL SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2014 - 05/2019] 

    Result: 

    A 

    See step  4

  4. TEST MODE INSPECTION (VEHICLE STABILITY CONTROL SYSTEM) 

    HINT: 

    When entering test mode, the skid control ECU (brake actuator 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 engine switch on (IG).
      2. Change the shift state to park (P).
      3. Check that the steering wheel is centered.
      4. Turn the engine switch off.
      5. Connect the Techstream to the DLC3.
      6. Turn the engine switch on (IG).
      7. Check that the parking brake is released.
      8. Turn the Techstream on.
      9. Switch the skid control ECU (brake actuator assembly) to Test Mode (Signal Check) using the Techstream.
      10. Enter the following menus: Chassis / ABS/VSC/TRAC / Utility / Signal Check.

        HINT: 

        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.

        Chassis > ABS/VSC/TRAC > Utility 

        Tester Display
        Signal Check
    2. Test Mode (Signal Check) Display Check
      1. Check that the ABS warning light, brake system warning light (red indicator) and slip indicator light come on for several seconds and then blink in the Test Mode pattern.

        HINT: 

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

    3. End of Test Mode (Signal Check)
      1. Turn the engine switch off and disconnect the Techstream.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  5

  5. CHECK FOR DTCs (PRE-COLLISION SYSTEM) 
    1. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [09/2017 - 05/2019]

      Body Electrical > Pre-Collision 2 > Clear DTCs 

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

      HINT: 

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

    3. Check for DTCs.

      Refer to DTC CHECK / CLEAR [09/2017 - 05/2019]

      Body Electrical > Pre-Collision 2 > Trouble Codes 

      Result

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

    Result: 

    A 

    END 

    Result: 

    B 

    See step  6

  6. REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY 
    1. Replace the millimeter wave radar sensor assembly.

      Refer to REMOVAL [09/2017 - 05/2019]

    2. Adjust the millimeter wave radar sensor assembly.

      Refer to ADJUSTMENT [09/2017 - 05/2019]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  7

  7. CHECK FOR DTCs (PRE-COLLISION SYSTEM) 
    1. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [09/2017 - 05/2019]

      Body Electrical > Pre-Collision 2 > Clear DTCs 

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

      HINT: 

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

    3. Check for DTCs.

      Refer to DTC CHECK / CLEAR [09/2017 - 05/2019]

      Body Electrical > Pre-Collision 2 > Trouble Codes 

      Result

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

    Result: 

    A 

    END (MILLIMETER WAVE RADAR SENSOR ASSEMBLY WAS DEFECTIVE) 

    Result: 

    B 

    See step  8

  8. REPLACE DRIVING SUPPORT ECU ASSEMBLY 
    1. Replace the driving support ECU assembly.

      Refer to REMOVAL [09/2017 - 05/2019]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  9

  9. CHECK FOR DTCs (PRE-COLLISION SYSTEM) 
    1. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [09/2017 - 05/2019]

      Body Electrical > Pre-Collision 2 > Clear DTCs 

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

      HINT: 

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

    3. Check for DTCs.

      Refer to DTC CHECK / CLEAR [09/2017 - 05/2019]

      Body Electrical > Pre-Collision 2 > Trouble Codes 

      Result

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

    Result: 

    A 

    END (DRIVING SUPPORT ECU ASSEMBLY WAS DEFECTIVE) 

    Result: 

    B 

    See step  10

  10. REPLACE FORWARD RECOGNITION CAMERA 
    1. Replace the forward recognition camera.

      Refer to REMOVAL [09/2017 - 05/2019]

    2. Perform Forward Recognition Camera Learning.

      Refer to ADJUSTMENT (SEQUENTIAL RECOGNITION) [09/2017 - 05/2019]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  11

  11. CHECK FOR DTCs (PRE-COLLISION SYSTEM) 
    1. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [09/2017 - 05/2019]

      Body Electrical > Pre-Collision 2 > Clear DTCs 

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

      HINT: 

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

    3. Check for DTCs.

      Refer to DTC CHECK / CLEAR [09/2017 - 05/2019]

      Body Electrical > Pre-Collision 2 > Trouble Codes 

      Result

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

    Result: 

    A 

    END (FORWARD RECOGNITION CAMERA WAS DEFECTIVE) 

    Result: 

    B 

    See step  12

  12. REPLACE SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY) 
    1. Replace the skid control ECU (brake actuator assembly).

      Refer to REMOVAL [10/2014 - 05/2019]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    END (SKID CONTROL ECU WAS DEFECTIVE) 

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