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DTC U1002: Lost Communication with Gateway Module [08/2019 - ]: Procedure

  1. CHECK CAN BUS LINE (MALFUNCTION CONFIRMATION) 
    1. Turn the engine switch off.
    2. Disconnect the cable from the negative (-) battery terminal.
    3. Measure the resistance according to the value(s) in the table below.
      GTY954629Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Driving Support ECU Assembly)

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      G114-8 (CA1P) - G114-9 (CA1N) Cable disconnected from negative (-) battery terminal 54 to 69 Ω Below 54 Ω:
      Short circuit between bus lines
      70 Ω or more:
      Open circuit in a main bus line or driving support ECU assembly branch line
      G114-8 (CA1P) - G114-28 (GND) Cable disconnected from negative (-) battery terminal 200 Ω or higher Below 200 Ω:
      CANH ground short
      G114-9 (CA1N) - G114-28 (GND) Cable disconnected from negative (-) battery terminal 200 Ω or higher Below 200 Ω:
      CANH ground short
      G114-8 (CA1P) - G114-7 (B) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Below 6 kΩ:
      CANH +B short
      G114-9 (CA1N) - G114-7 (B) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Below 6 kΩ:
      CANH +B short
    4. Connect the cable to the negative (-) battery terminal.

      Result

      Result Proceed to
      OK A
      NG (Open circuit in main line or Driving support ECU assembly branch line) B
      NG (Short circuit between main lines) C
      NG (Short to +B or ground) D

    Result: 

    B 

    See step  3

    Result: 

    C 

    See step  8

    Result: 

    D 

    See step  12

    Result: 

    A 

    See step  2

  2. CHECK FOR DTCs (PRE-COLLISION SYSTEM) 
    1. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [08/2019 - ]

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

      HINT: 

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

    3. Check for DTCs.

      Refer to DTC CHECK / CLEAR [08/2019 - ]

      Result

      Result Proceed to
      DTC U1002 is not output A
      DTC U1002 is output B

    Result: 

    A 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2019 - 08/2020]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2020 - 08/2021]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2021 - 08/2022]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2022 - ] 

    Result: 

    B 

    REPLACE DRIVING SUPPORT ECU ASSEMBLY. Refer to  REMOVAL [08/2019 - ] 

  3. CHECK FOR OPEN IN CAN BUS BRANCH LINES (DRIVING SUPPORT ECU ASSEMBLY) 
    1. Disconnect the cable from the negative (-) battery terminal.
    2. Disconnect the G114 driving support ECU assembly connector.
      GTY956934Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Driving Support ECU Assembly)
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G114-8 (CA1P) - G114-9 (CA1N) Cable disconnected from negative (-) battery terminal 108 to 132 Ω

      HINT: 

      If the resistance is between 108 and 132 Ω, there may be an open in a CAN bus main line. If the value is 132 Ω or more, there may be an open in a CAN bus branch line between the No. 5 CAN junction connector and the driving support ECU or a connector may be disconnected.

    4. Connect the G114 driving support ECU assembly connector.
    5. Connect the cable to the negative (-) battery terminal.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  7

    Result: 

    OK 

    See step  4

  4. CHECK FOR OPEN IN CAN BUS MAIN LINES (JUNCTION CONNECTOR) 
    1. Disconnect the cable from the negative (-) battery terminal.
    2. Disconnect the G154 junction connector.
      GTY957273Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Junction Connector)
      *b to Forward Recognition Camera
      *c to Millimeter Wave Radar Sensor Assembly
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition Connected to
      G154-7 (CANH) - G154-18 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Forward Recognition Camera
      G154-9 (CA1P) - G154-20 (CA1N) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Millimeter Wave Radar Sensor Assembly
    4. Connect the G154 No. 5 CAN junction connector.
    5. Connect the cable to the negative (-) battery terminal.

      Result

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

    Result: 

    A 

    REPLACE JUNCTION CONNECTOR 

    Result: 

    C 

    See step  6

    Result: 

    B 

    See step  5

  5. CHECK FOR OPEN IN CAN BUS MAIN LINES (FORWARD RECOGNITION CAMERA) 
    1. Disconnect the cable from the negative (-) battery terminal.
    2. Disconnect the W19 forward recognition camera connector.
      GTY956436Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Forward Recognition Camera)
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      W19-6 (CANH) - W19-12 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
    4. Connect the W19 forward recognition camera connector.
    5. Connect the cable to the negative (-) battery terminal.

      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 (JUNCTION CONNECTOR - FORWARD RECOGNITION CAMERA) 

  6. CHECK FOR OPEN IN CAN BUS MAIN LINES (MILLIMETER WAVE RADAR SENSOR ASSEMBLY) 
    1. Disconnect the cable from the negative (-) battery terminal.
    2. Disconnect the B13 millimeter wave radar sensor assembly connector.
      GTY946729Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Millimeter Wave Radar Sensor Assembly)
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      B13-5 (CA1P) - B13-6 (CA1N) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
    4. Connect the B13 millimeter wave radar sensor assembly connector.
    5. Connect the cable to the negative (-) battery terminal.

      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 (JUNCTION CONNECTOR - MILLIMETER WAVE RADAR SENSOR ASSEMBLY) 

  7. CHECK FOR OPEN IN CAN BUS BRANCH LINES (DRIVING SUPPORT ECU ASSEMBLY) 
    1. Disconnect the cable from the negative (-) battery terminal.
    2. Disconnect the G114 driving support ECU assembly connector.
      GTY956936Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Driving Support ECU Assembly)
    3. Disconnect the G154 junction connector.
      GTY956142Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Junction Connector)
      *b to Driving Support ECU Assembly
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G154-2 (CA1P) - G114-8 (CA1P) Cable disconnected from negative (-) battery terminal Below 1 Ω
      G154-13 (CA1N) - G114-9 (CA1N) Cable disconnected from negative (-) battery terminal Below 1 Ω
    5. Connect the G154 junction connector.
    6. Connect the G114 driving support ECU assembly connector.
    7. Connect the cable to the negative (-) battery terminal.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE JUNCTION CONNECTOR 

    Result: 

    NG 

    REPAIR OR REPLACE CAN BUS BRANCH WIRE (JUNCTION CONNECTOR - DRIVING SUPPORT ECU ASSEMBLY) 

  8. CHECK FOR SHORT BETWEEN CAN BUS LINES (FORWARD RECOGNITION CAMERA) 
    1. Disconnect the cable from the negative (-) battery terminal.
    2. Disconnect the W19 forward recognition camera connector.
      GTY956435Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Forward Recognition Camera)
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      W19-6 (CANH) - W19-12 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
    4. Connect the W19 forward recognition camera connector.
    5. Connect the cable to the negative (-) battery terminal.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

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

    Result: 

    NG 

    See step  9

  9. CHECK FOR SHORT BETWEEN CAN BUS LINES (JUNCTION CONNECTOR) 
    1. Disconnect the cable from the negative (-) battery terminal.
    2. Disconnect the G154 junction connector.
      GTY957279Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Junction Connector)
      *b to Forward Recognition Camera
      *c to Millimeter Wave Radar Sensor Assembly
      *d to Driving Support ECU Assembly
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition Connected to
      G154-7 (CANH) - G154-18 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Forward Recognition Camera
      G154-9 (CA1P) - G154-20 (CA1N) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Millimeter Wave Radar Sensor Assembly
      G154-8 (CA1P) - G154-15 (CA1N) Cable disconnected from negative (-) battery terminal 200 Ω or higher Driving Support ECU Assembly
    4. Connect the G154 CAN junction connector.
    5. Connect the cable to the negative (-) battery terminal.

      Result

      Result Proceed to
      OK A
      NG (Forward Recognition Camera Main Line) B
      NG (Millimeter Wave Radar Sensor Assembly Main Line) C
      NG (Driving Support ECU Assembly Branch Line) D

    Result: 

    A 

    REPLACE JUNCTION CONNECTOR 

    Result: 

    B 

    REPAIR OR REPLACE CAN BUS MAIN LINE OR CONNECTOR (JUNCTION CONNECTOR - FORWARD RECOGNITION CAMERA) 

    Result: 

    D 

    See step  11

    Result: 

    C 

    See step  10

  10. CHECK FOR SHORT BETWEEN CAN BUS LINES (MILLIMETER WAVE RADAR SENSOR ASSEMBLY) 
    1. Disconnect the cable from the negative (-) battery terminal.
    2. Disconnect the B13 millimeter wave radar sensor assembly connector.
      GTY946716Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Millimeter Wave Radar Sensor Assembly)
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      B13-5 (CA1P) - B13-6 (CA1N) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
    4. Connect the B13 millimeter wave radar sensor assembly connector.
    5. Connect the cable to the negative (-) battery terminal.

      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 (JUNCTION CONNECTOR - MILLIMETER WAVE RADAR SENSOR ASSEMBLY) 

  11. CHECK FOR SHORT BETWEEN CAN BUS LINES (DRIVING SUPPORT ECU ASSEMBLY) 
    1. Disconnect the cable from the negative (-) battery terminal.
    2. Disconnect the G114 driving support ECU assembly connector.
      GTY956937Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Driving Support ECU Assembly)
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G114-8 (CA1P) - G114-9 (CA1N) Cable disconnected from negative (-) battery terminal 54 to 69 Ω
    4. Connect the G114 driving support ECU assembly connector.
    5. Connect the cable to the negative (-) battery terminal.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE DRIVING SUPPORT ECU ASSEMBLY. Refer to  REMOVAL [08/2019 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE CAN BUS BRANCH LINE OR CONNECTOR (JUNCTION CONNECTOR - DRIVING SUPPORT ECU ASSEMBLY) 

  12. CHECK FOR SHORT IN CAN BUS LINE (FORWARD RECOGNITION CAMERA) 
    1. Disconnect the cable from the negative (-) battery terminal.
    2. Disconnect the W19 forward recognition camera connector.
      GTY956433Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Forward Recognition Camera)
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      W19-6 (CANH) - Body ground Cable disconnected from negative (-) battery terminal 200 Ω or higher
      W19-12 (CANL) - Body ground Cable disconnected from negative (-) battery terminal 200 Ω or higher
      W19-6 (CANH) - +B Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      W19-12 (CANL) - +B Cable disconnected from negative (-) battery terminal 6 kΩ or higher
    4. Connect the W19 forward recognition camera connector.
    5. Connect the cable to the negative (-) battery terminal.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

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

    Result: 

    NG 

    See step  13

  13. CHECK FOR SHORT IN CAN BUS LINE (JUNCTION CONNECTOR) 
    1. Disconnect the cable from the negative (-) battery terminal.
    2. Disconnect the G154 junction connector.
      GTY957279Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Junction Connector)
      *b to Forward Recognition Camera
      *c to Millimeter Wave Radar Sensor Assembly
      *d to Driving Support ECU Assembly
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition Connected to
      G154-7 (CANH) - Body ground Cable disconnected from negative (-) battery terminal 200 Ω or higher Forward Recognition Camera
      G154-18 (CANL) - Body ground
      G154-7 (CANH) - +B 6 kΩ or higher
      G154-18 (CANL) - +B
      G154-9 (CA1P) - Body ground Cable disconnected from negative (-) battery terminal 200 Ω or higher Millimeter Wave Radar Sensor Assembly
      G154-20 (CA1N) - Body ground
      G154-9 (CA1P) - +B 6 kΩ or higher
      G154-20 (CA1N) - +B
      G154-8 (CA1P) - Body ground Cable disconnected from negative (-) battery terminal 200 Ω or higher Driving Support ECU Assembly
      G154-15 (CA1N) - Body ground
      G154-8 (CA1P) - +B 6 kΩ or higher
      G154-15 (CA1N) - +B
    4. Connect the G154 junction connector.
    5. Connect the cable to the negative (-) battery terminal.

      Result

      Result Proceed to
      OK A
      NG (Forward Recognition Camera Main Line) B
      NG (Millimeter Wave Radar Sensor Assembly Main Line) C
      NG (Driving Support ECU Assembly Branch Line) D

    Result: 

    A 

    REPLACE JUNCTION CONNECTOR 

    Result: 

    B 

    REPAIR OR REPLACE CAN BUS MAIN LINE OR CONNECTOR (JUNCTION CONNECTOR - FORWARD RECOGNITION CAMERA) 

    Result: 

    D 

    See step  15

    Result: 

    C 

    See step  14

  14. CHECK FOR SHORT IN CAN BUS LINE (MILLIMETER WAVE RADAR SENSOR ASSEMBLY) 
    1. Disconnect the cable from the negative (-) battery terminal.
    2. Disconnect the B13 millimeter wave radar sensor assembly connector.
      GTY946716Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Millimeter Wave Radar Sensor Assembly)
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      B13-5 (CA1P) - Body ground Cable disconnected from negative (-) battery terminal 200 Ω or higher
      B13-6 (CA1N) - Body ground Cable disconnected from negative (-) battery terminal 200 Ω or higher
      B13-5 (CA1P) - +B Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      B13-6 (CA1N) - +B Cable disconnected from negative (-) battery terminal 6 kΩ or higher
    4. Connect the B13 millimeter wave radar sensor assembly connector.
    5. Connect the cable to the negative (-) battery terminal.

      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 (JUNCTION CONNECTOR - MILLIMETER WAVE RADAR SENSOR ASSEMBLY) 

  15. CHECK FOR SHORT IN CAN BUS LINE (DRIVING SUPPORT ECU ASSEMBLY) 
    1. Disconnect the cable from the negative (-) battery terminal.
    2. Disconnect the G114 driving support ECU assembly connector.
      GTY956937Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Driving Support ECU Assembly)
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G114-8 (CA1P) - Body ground Cable disconnected from negative (-) battery terminal 200 Ω or higher
      G114-9 (CA1N) - Body ground Cable disconnected from negative (-) battery terminal 200 Ω or higher
      G114-8 (CA1P) - +B Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      G114-9 (CA1N) - +B Cable disconnected from negative (-) battery terminal 6 kΩ or higher
    4. Connect the G114 driving support ECU assembly connector.
    5. Connect the cable to the negative (-) battery terminal.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE DRIVING SUPPORT ECU ASSEMBLY. Refer to  REMOVAL [08/2019 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE CAN BUS BRANCH LINE OR CONNECTOR (JUNCTION CONNECTOR - DRIVING SUPPORT ECU ASSEMBLY) 

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