LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 2021 >> RX 350 Base, AWD >> Repair and Diagnosis >> Accessories & Equipment >> Cruise Control Systems >> Front Radar Sensor System - Diagnostic Codes >> Front Radar Sensor System >> DTC U0104-87: Lost Communication with Cruise Control Module Missing Message [08/2019 - ] >> Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

DTC U0104-87: Lost Communication with Cruise Control Module Missing Message [08/2019 - ]: Procedure

  1. CHECK FOR DTCs 
    1. Check for pre-collision system DTCs.

      Body Electrical > Pre-Collision System > Trouble Codes 

      Result

      Result Proceed to
      DTC U0235-87 is output A
      DTC U0235-87 is not output B

    Result: 

    B 

    See step  5

    Result: 

    A 

    See step  2

  2. CHECK CAN BUS LINES (NO. 1 CAN JUNCTION CONNECTOR) 
    GTY949679Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *1 DLC3 - -
    *a Front view of wire harness connector
    (to No. 1 CAN Junction Connector)    		 *b to Millimeter Wave Radar Sensor Assembly
    *c to Forward Recognition Camera - -
    1. Disconnect the cable from the negative (-) battery terminal.
    2. Disconnect the A86 No. 1 CAN junction connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A86-1 - A86-12 Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      A86-5 - A86-16 Cable disconnected from negative (-) battery terminal 108 to 132 Ω
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A86-1 - J141-4(CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      A86-12 - J141-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      A86-1 - J141-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      A86-12 - J141-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      A86-5 - J141-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      A86-16 - J141-4(CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      A86-5 - J141-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      A86-16 - J141-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher
    5. Connect the A86 No. 1 CAN junction connector.

      Result

      Result Proceed to
      OK A
      NG (Connected to: Forward Recognition Camera) B
      NG (Connected to: Millimeter Wave Radar Sensor Assembly) C

    Result: 

    A 

    REPLACE NO. 1 CAN JUNCTION CONNECTOR 

    Result: 

    C 

    See step  4

    Result: 

    B 

    See step  3

  3. CHECK CAN BUS LINES (FORWARD RECOGNITION CAMERA - NO. 1 CAN JUNCTION CONNECTOR) 
    GTY949681Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *1 DLC3 - -
    *a Front view of wire harness connector
    (to Forward Recognition Camera)    		 - -
    1. Disconnect the U14 forward recognition camera connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      U14-6 (CANH) - U14-12 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132Ω
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      U14-6 (CANH) - J141-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      U14-12 (CANL) - J141-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      U14-6 (CANH) - J141-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      U14-12 (CANL) - J141-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher
    4. Connect the U14 forward recognition camera connector.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE FORWARD RECOGNITION CAMERA. Refer to  REMOVAL [08/2019 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE CAN BUS MAIN LINE OR CONNECTOR (FORWARD RECOGNITION CAMERA - NO. 1 CAN JUNCTION CONNECTOR) 

  4. CHECK CAN BUS LINES (MILLIMETER WAVE RADAR SENSOR ASSEMBLY - NO. 1 CAN JUNCTION CONNECTOR) 
    GTY949663Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *1 DLC3 - -
    *a Front view of wire harness connector
    (to Millimeter Wave Radar Sensor Assembly)    		 - -
    1. Disconnect the A70 millimeter wave radar sensor assembly connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A70-5 (CA1P) - A70-6 (CA1N) Cable disconnected from negative (-) battery terminal 108 to 132Ω
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A70-5 (CA1P) - J141-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      A70-6 (CA1N) - J141-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      A70-5 (CA1P) - J141-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      A70-6 (CA1N) - J141-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher
    4. Connect the A70 millimeter wave radar sensor assembly connector.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY. Refer to  REMOVAL [08/2019 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE CAN BUS MAIN LINE OR CONNECTOR (MILLIMETER WAVE RADAR SENSOR ASSEMBLY - NO. 1 CAN JUNCTION CONNECTOR) 

  5. CHECK CONNECTOR (FORWARD RECOGNITION CAMERA) 
    1. Check the locking part and terminals of the forward recognition camera connector.
      NOTE:
      • Make sure the connector is not loose or disconnected.
      • Make sure that the connector and terminals are not deformed or corroded.

      OK

      The connector and terminals are normal.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (FORWARD RECOGNITION CAMERA) 

    Result: 

    OK 

    See step  6

  6. CHECK HARNESS AND CONNECTOR (FORWARD RECOGNITION CAMERA POWER SOURCE CIRCUIT) 
    GTY947130Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Front view of wire harness connector
    (to Forward Recognition Camera)
    1. Disconnect the cable from the negative (-) battery terminal.
    2. Disconnect the U14 forward recognition camera connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      U14-10 (GND) - Body ground Always Below 1 Ω
    4. Connect the cable to the negative (-) battery terminal.
    5. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      U14-7 (IGB) - Body ground Engine switch on (IG) 11 to 14 V
    6. Connect the U14 forward recognition camera connector.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  7

  7. INSPECT FORWARD RECOGNITION CAMERA (WAVEFORM) 
    Fig 1: Forward Recognition Camera Terminals With Waveform
    GTY960453Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Front view of wire harness connector
    (to No. 1 CAN Junction Connector)    		 *b Waveform
    *c to Forward Recognition Camera - -
    1. Turn the engine switch off.
    2. Disconnect the A86 No. 1 CAN junction connector.
    3. Turn the engine switch on (IG).
    4. Using an oscilloscope, measure the waveform at the A86 No. 1 CAN junction connector.

      Measurement Condition

      Tester Connection Condition Tool Setting
      A86-1 - Body ground Engine switch on (IG) 1 V/DIV., 100 μs/DIV.
      NOTE:

      The oscilloscope waveform is for reference only and does not include noise, fluctuations, etc.

      OK

      A waveform similar to that in the illustration can be observed.

    5. Connect the A86 No. 1 CAN junction connector.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY. Refer to  REMOVAL [08/2019 - ] 

    Result: 

    NG 

    REPLACE FORWARD RECOGNITION CAMERA. Refer to  REMOVAL [08/2019 - ] 

scientia non olet · About LEMON Manuals