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DTC U0104-87: Lost Communication with Cruise Control Module Missing Message [10/2023 - ]: Procedure

WARNING: This page is about a different car, the 2024 Lexus LS 500. However, it is still accessible from the selected car via links, so may be relevant.
  1. CONFIRM MODEL 
    1. Choose the model to be inspected.

      Result

      Result Proceed to
      w Advanced Park A
      w/o Advanced Park B

    Result: 

    B 

    See step  8

    Result: 

    A 

    See step  2

  2. CHECK FOR DTCs 
    1. Read each DTC and check the diagnosis pattern using the table below.

      Body Electrical > Front Radar Sensor > Trouble Codes 

      Chassis > Front Recognition Camera > Trouble Codes 

      Body Electrical > Clearance Warning > Trouble Codes 

      Chassis > Circumference Monitoring Camera Control Module > Trouble Codes 

      Pattern DTC output part name
      (Display on GTS)
      Front Radar Sensor Front Recognition Camera Clearance Warning Circumference Monitoring Camera Control Module
      Pattern 1 U0104-87 U0235-87 U1179-87 U11B6-87
      Pattern 2 U0104-87 - - -

      Result

      Result Proceed to
      Pattern 1 A
      Pattern 2 B

    Result: 

    A 

    GO TO FRONT CAMERA SYSTEM. Refer to  DTC U0235-87: Lost Communication with Cruise Control Front Distance Range Sensor Single Sensor or Center Missing Message [10/2023 - ] 

    Result: 

    B 

    See step  3

  3. CHECK CONNECTION OF CONNECTORS 
    1. Check that the connectors are properly connected to the forward recognition camera and millimeter wave radar sensor assembly.

      OK

      The connectors are properly connected

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    CONNECT CONNECTORS PROPERLY 

    Result: 

    OK 

    See step  4

  4. CLEAR DTC 
    1. Read each DTC and check the diagnosis pattern using the table below.

      Body Electrical > Front Radar Sensor > Clear DTCs 

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  5

  5. CHECK FOR DTCs 

    Pre-procedure1

    1. Turn the ignition switch off.
    2. Turn the ignition switch to ON.
    3. Make sure that the DTC detection conditions are met.

      HINT: 

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

      Procedure1

    4. Check for DTCs.

      Body Electrical > Front Radar Sensor > Trouble Codes 

      Result

      Result Proceed to
      U0104-87 is not output A
      U0104-87 is output B

      Post-procedure1

    5. None

    Result: 

    A 

    END 

    Result: 

    B 

    See step  6

  6. CHECK CAN MAIN WIRE (MILLIMETER WAVE RADAR SENSOR ASSEMBLY) 

    Pre-procedure1

    1. Disconnect the cable from the negative (-) battery terminal.
    2. Disconnect the C17 millimeter wave radar sensor assembly connector.

      Procedure1

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      C17-8 (CA1P) - C17-7 (CA1N) Cable disconnected from negative (-) battery terminal 108 to 132 Ω

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    4. None

    Result: 

    NG 

    REPAIR OR REPLACE CAN BUS HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  7

  7. CHECK FORWARD RECOGNITION CAMERA 

    Pre-procedure1

    1. Disconnect the C17 millimeter wave radar sensor assembly connector.

      Procedure1

    2. Using an oscilloscope, check the waveform.

      OK

      Tester Connection Condition Tool Setting Specified Condition
      C17-8 (CA1P) - C17-7 (CA1N) Ignition switch ON 1V/DIV., 100μs./DIV. Pulse generation

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    3. None

    Result: 

    OK 

    REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY. Refer to  REMOVAL [10/2023 - ] 

    Result: 

    NG 

    REPLACE FORWARD RECOGNITION CAMERA. Refer to  REMOVAL [10/2023 - ] 

  8. CHECK FOR DTCs 
    1. Read each DTC and check the diagnosis pattern using the table below.

      Body Electrical > Front Radar Sensor > Trouble Codes 

      Chassis > Front Recognition Camera > Trouble Codes 

      Pattern DTC output part name
      (Display on GTS)
      Front Radar Sensor Front Recognition Camera
      Pattern 1 U0104-87 U0235-87
      Pattern 2 U0104-87 -

      Result

      Result Proceed to
      Pattern 1 A
      Pattern 2 B

    Result: 

    A 

    GO TO FRONT CAMERA SYSTEM. Refer to  DTC U0235-87: Lost Communication with Cruise Control Front Distance Range Sensor Single Sensor or Center Missing Message [10/2023 - ] 

    Result: 

    B 

    See step  9

  9. CHECK CONNECTION OF CONNECTORS 
    1. Check that the connectors are properly connected to the forward recognition camera and millimeter wave radar sensor assembly.

      OK

      The connectors are properly connected

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    CONNECT CONNECTORS PROPERLY 

    Result: 

    OK 

    See step  10

  10. CLEAR DTC 
    1. Read each DTC and check the diagnosis pattern using the table below.

      Body Electrical > Front Radar Sensor > Clear DTCs 

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  11

  11. CHECK FOR DTCs 

    Pre-procedure1

    1. Turn the ignition switch off.
    2. Turn the ignition switch to ON.
    3. Make sure that the DTC detection conditions are met.

      HINT: 

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

      Procedure1

    4. Check for DTCs.

      Body Electrical > Front Radar Sensor > Trouble Codes 

      Result

      Result Proceed to
      U0104-87 is not output A
      U0104-87 is output B

      Post-procedure1

    5. None

    Result: 

    A 

    END 

    Result: 

    B 

    See step  12

  12. CHECK CAN MAIN WIRE (MILLIMETER WAVE RADAR SENSOR ASSEMBLY) 

    Pre-procedure1

    1. Disconnect the cable from the negative (-) battery terminal.
    2. Disconnect the C17 millimeter wave radar sensor assembly connector.

      Procedure1

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      C17-8 (CA1P) - C17-7 (CA1N) Cable disconnected from negative (-) battery terminal 108 to 132 Ω

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    4. None

    Result: 

    NG 

    REPAIR OR REPLACE CAN BUS HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  13

  13. CHECK FORWARD RECOGNITION CAMERA 

    Pre-procedure1

    1. Disconnect the C17 millimeter wave radar sensor assembly connector.

      Procedure1

    2. Using an oscilloscope, check the waveform.

      OK

      Tester Connection Condition Tool Setting Specified Condition
      C17-8 (CA1P) - C17-7 (CA1N) Ignition switch ON 1V/DIV., 100μs./DIV. Pulse generation

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    3. None

    Result: 

    OK 

    REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY. Refer to  REMOVAL [10/2023 - ] 

    Result: 

    NG 

    REPLACE FORWARD RECOGNITION CAMERA. Refer to  REMOVAL [10/2023 - ] 

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