PRE-CRASH SAFETY SYSTEM, Diagnostic DTC:U1104

DTC Code DTC Name
U1104 Lost Communication with Driving Support ECU

DESCRIPTION

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

DTC No. DTC Detection Condition Trouble Area
U1104

  • 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.

  • 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 0.2 seconds.

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

  • CAN communication system

  • Millimeter wave radar sensor assembly

  • Forward recognition camera

  • Brake booster with master cylinder assembly (skid control ECU)

  • Driving support ECU assembly

  • Wire harness or connector

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.

  • When the forward recognition camera is replaced with a new one, adjustment of the Recognition Camera/Target Position Memory and Recognition Camera Axis Adjust must be performed Click here.

  • When replacing the millimeter wave radar sensor assembly with a new one, make sure to perform Adjust Millimeter Wave Radar Sensor Assembly Click here.

  • Confirm that the connectors are securely connected, as a partially connected connector is suspected for the cause of these DTCs.

PROCEDURE


  1. CHECK DTC OUTPUT (PRE-CRASH SAFETY SYSTEM)


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Body Electrical / Pre-Crash 2 / Trouble Codes.

    5. Check for DTCs Click here.

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

    B

    GO TO DIAGNOSTIC TROUBLE CODE CHART Click here

    A

  2. CHECK DTC OUTPUT (FRONT RECOGNITION CAMERA SYSTEM)


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Body Electrical / Front Recognition Camera / Trouble Codes.

    5. Check for DTCs Click here.

      Result
      Result Proceed to
      Front recognition camera system DTC are not output A
      Front recognition camera system DTC are output B

    B

    GO TO FRONT RECOGNITION CAMERA SYSTEM Click here

    A

  3. CHECK DTC OUTPUT (ELECTRONICALLY CONTROLLED BRAKE SYSTEM)


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Chassis / ABS/VSC/TRC / Trouble Codes.

    5. Check for DTCs Click here.

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

    B

    GO TO ELECTRONICALLY CONTROLLED BRAKE SYSTEM Click here

    A

  4. TEST MODE INSPECTION (ELECTRONICALLY CONTROLLED BRAKE SYSTEM)

    Tech Tips

    Enter Test Mode to check if the electronically controlled brake system is operating properly.


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

      Note

      Do not start the engine.

    3. Turn the GTS on.

    4. Switch the skid control ECU (brake booster with master cylinder assembly) to Test Mode using the GTS. Enter the following menus: Chassis / ABS/VSC/TRC / Utility / Test Mode.

      Note

      Do not enter Test Mode with the engine started.

      Tech Tips

      Test mode procedure Click here.

    5. After Test Mode has been entered, keep the vehicle stationary on a level surface for 5 seconds or more.

    6. Perform the steps displayed on the GTS to end Test Mode.

    7. Turn the power switch off.


    NEXT

  5. CHECK DTC OUTPUT (PRE-CRASH SAFETY SYSTEM)


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Body Electrical / Pre-Crash 2 / Trouble Codes.

    5. Clear the DTCs Click here.

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

      Tech Tips

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

    7. Check for DTCs Click here.

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

    B

    END

    A

  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.


    NEXT

  7. CHECK DTC OUTPUT (PRE-CRASH SAFETY SYSTEM)


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Body Electrical / Pre-Crash 2 / Trouble Codes.

    5. Clear the DTCs Click here.

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

      Tech Tips

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

    7. Check for DTCs Click here.

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

    B

    END (MILLIMETER WAVE RADAR SENSOR ASSEMBLY WAS DEFECTIVE)

    A

  8. REPLACE DRIVING SUPPORT ECU ASSEMBLY


    1. Replace the driving support ECU assembly Click here.


    NEXT

  9. CHECK DTC OUTPUT (PRE-CRASH SAFETY SYSTEM)


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Body Electrical / Pre-Crash 2 / Trouble Codes.

    5. Clear the DTCs Click here.

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

      Tech Tips

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

    7. Check for DTCs Click here.

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

    B

    END (DRIVING SUPPORT ECU ASSEMBLY WAS DEFECTIVE)

    A

  10. REPLACE FORWARD RECOGNITION CAMERA


    1. Replace the forward recognition camera Click here.

    2. Adjust the forward recognition camera Click here.


    NEXT

  11. CHECK DTC OUTPUT (PRE-CRASH SAFETY SYSTEM)


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Body Electrical / Pre-Crash 2 / Trouble Codes.

    5. Clear the DTCs Click here.

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

      Tech Tips

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

    7. Check for DTCs Click here.

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

    B

    END (FORWARD RECOGNITION CAMERA WAS DEFECTIVE)

    A

  12. REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY


    1. Replace the brake booster with master cylinder assembly.

      for LHD: Click here

      for RHD: Click here


    NEXT

    END (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY WAS DEFECTIVE)