PRE-CRASH SAFETY SYSTEM, Diagnostic DTC:U1104

DTC Code DTC Name
U1104 Lost Communication with Driving Support ECU

DESCRIPTION


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 ignition switch is ON, a communication error between the driving support ECU assembly and the millimeter wave radar sensor assembly is detected for approximately 0.2 seconds.

  • When the ignition switch is ON, a communication error between the driving support ECU assembly and the forward recognition camera is detected for approximately 0.3 seconds.

  • for 2TR-FE:

    When the ignition switch is ON, a communication error between the driving support ECU assembly and the skid control ECU (brake actuator assembly) is detected for approximately 1.5 seconds.

  • except 2TR-FE:

    When the ignition switch is ON, a communication error between the driving support ECU assembly and the skid control ECU (master cylinder solenoid) is detected for approximately 1.5 seconds.

  • CAN communication system

  • Millimeter wave radar sensor assembly

  • Forward recognition camera

  • Skid control ECU assembly (brake actuator assembly) (for 2TR-FE)

  • Skid control ECU assembly (master cylinder solenoid) (except 2TR-FE)

  • Driving support ECU assembly

  • Harness or connector

  • Forward recognition camera system

  • Vehicle stability control system

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.

    Click here

  • 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.

    Click here

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

PROCEDURE


  1. CHECK FOR DTCs (PRE-CRASH SAFETY SYSTEM)


    1. Check for DTCs.

      Click here

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

    A

    GO TO DIAGNOSTIC TROUBLE CODE CHART Click here

    B

  2. CHECK FOR DTCs (FORWARD RECOGNITION CAMERA SYSTEM)


    1. Check for DTCs.

      Click here

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

    B

    GO TO FORWARD RECOGNITION CAMERA SYSTEM Click here

    A

  3. CHECK FOR DTCs (VEHICLE STABILITY CONTROL SYSTEM)


    1. Check for DTCs.

      for 2TR-FE: Click here

      except 2TR-FE: Click here

      Result
      Result Proceed to
      Vehicle stability control system DTC are not output A
      Vehicle stability control system DTC are output (for 2TR-FE) B
      Vehicle stability control system DTC are output (except 2TR-FE) C

    B

    GO TO VEHICLE STABILITY CONTROL SYSTEM Click here

    C

    GO TO VEHICLE STABILITY CONTROL SYSTEM Click here

    A

  4. TEST MODE INSPECTION (VEHICLE STABILITY CONTROL SYSTEM)

    Tech Tips


    • for 2TR-FE:

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

    • except 2TR-FE:

      When entering test mode, the master cylinder solenoid communicates with the driving support ECU assembly to judge whether the vehicle is equipped with the pre-crash safety 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 ignition switch ON.

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

      3. Check that the steering wheel is centered.

      4. Turn the ignition switch off.

      5. Connect the GTS to the DLC3.

      6. Turn the ignition switch ON.

      7. Check that the parking brake is released.

      8. Turn the GTS on.

      9. for 2TR-FE:

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

      10. except 2TR-FE:

        Switch the skid control ECU (master cylinder solenoid) to Test Mode (Signal Check) using the GTS.

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

        Tech Tips

        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.

    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.

        Tech Tips

        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 ignition switch off and disconnect the GTS.

      Result
      Proceed to
      NEXT

    NEXT

  5. CHECK FOR DTCs (PRE-CRASH SAFETY SYSTEM)


    1. Clear the DTCs.

      Click here

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

      Tech Tips

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

    3. Check for DTCs.

      Click here

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

    A

    END

    B

  6. REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY


    1. Replace the millimeter wave radar sensor assembly.

      Click here

    2. Adjust the millimeter wave radar sensor assembly.

      Click here

      Result
      Proceed to
      NEXT

    NEXT

  7. CHECK FOR DTCs (PRE-CRASH SAFETY SYSTEM)


    1. Clear the DTCs.

      Click here

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

      Tech Tips

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

    3. Check for DTCs.

      Click here

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

    A

    END (MILLIMETER WAVE RADAR SENSOR ASSEMBLY WAS DEFECTIVE)

    B

  8. REPLACE DRIVING SUPPORT ECU ASSEMBLY


    1. Replace the driving support ECU assembly.

      Click here

      Result
      Proceed to
      NEXT

    NEXT

  9. CHECK FOR DTCs (PRE-CRASH SAFETY SYSTEM)


    1. Clear the DTCs.

      Click here

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

      Tech Tips

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

    3. Check for DTCs.

      Click here

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

    A

    END (DRIVING SUPPORT ECU ASSEMBLY WAS DEFECTIVE)

    B

  10. REPLACE FORWARD RECOGNITION CAMERA


    1. Replace the forward recognition camera.

      Click here

    2. Perform Forward Recognition Camera Learning.

      Click here

      Result
      Proceed to
      NEXT

    NEXT

  11. CHECK FOR DTCs (PRE-CRASH SAFETY SYSTEM)


    1. Clear the DTCs.

      Click here

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

      Tech Tips

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

    3. Check for DTCs.

      Click here

      Result
      Result Proceed to
      DTC U1104 is not output A
      DTC U1104 is output (for 2TR-FE) B
      DTC U1104 is output (except 2TR-FE) C

    A

    END (FORWARD RECOGNITION CAMERA WAS DEFECTIVE)

    C

    REPLACE MASTER CYLINDER SOLENOID Click here

    B

  12. REPLACE BRAKE ACTUATOR ASSEMBLY


    1. Replace the brake actuator assembly.

      Click here

      Result
      Proceed to
      NEXT

    NEXT

    END (BRAKE ACTUATOR ASSEMBLY WAS DEFECTIVE)

  13. REPLACE MASTER CYLINDER SOLENOID


    1. Replace the master cylinder solenoid.

      for LHD: Click here

      for RHD: Click here

      Result
      Proceed to
      NEXT

    NEXT

    END (MASTER CYLINDER SOLENOID)