LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 2021 >> RX 450h Base >> 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 (-) auxiliary 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 (-) auxiliary battery terminal 108 to 132 Ω
      A86-5 - A86-16 Cable disconnected from negative (-) auxiliary 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 (-) auxiliary battery terminal 200 Ω or higher
      A86-12 - J141-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      A86-1 - J141-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      A86-12 - J141-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      A86-5 - J141-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      A86-16 - J141-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      A86-5 - J141-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      A86-16 - J141-16 (BAT) Cable disconnected from negative (-) auxiliary 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 (-) auxiliary 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 (-) auxiliary battery terminal 200 Ω or higher
      U14-12 (CANL) - J141-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      U14-6 (CANH) - J141-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      U14-12 (CANL) - J141-16 (BAT) Cable disconnected from negative (-) auxiliary 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 (-) auxiliary 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 (-) auxiliary battery terminal 200 Ω or higher
      A70-6 (CA1N) - J141-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      A70-5 (CA1P) - J141-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      A70-6 (CA1N) - J141-16 (BAT) Cable disconnected from negative (-) auxiliary 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 (-) auxiliary 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 (-) auxiliary 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 Power 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) 
    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 power switch off.
    2. Disconnect the A86 No. 1 CAN junction connector.
    3. Turn the power 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 Power 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