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DTC U1002: Lost Communication with Gateway Module (Sensor Bus): Procedure

  1. DISCONNECT CABLE FROM NEGATIVE BATTERY TERMINAL 
    1. Disconnect the cable from the negative (-) battery terminal before measuring the resistances of the main wire and the branch wire.
      WARNING:

      Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

      NOTE:
      • w/ Navigation System:

        After the engine switch is turned off, the display and navigation module display records various types of memory and settings. As a result, after turning the engine switch off, be sure to wait for the time specified in the following table before disconnecting the cable from the negative (-) battery terminal.

        Waiting Time before Disconnecting Cable from Negative (-) Battery Terminal

        Condition Waiting Time
        Vehicle enrolled in safety connect system 6 minutes
        Vehicle not enrolled in safety connect system 1 minute
      • When disconnecting the cable, some systems need to be initialized after the cable is reconnected. Refer to INITIALIZATION .

    NEXT: Go to next step 

  2. CHECK FOR CAN BUS WIRE (MAIN WIRE FOR DISCONNECTION, BUS LINE FOR SHORT CIRCUIT) 
    1. Measure the resistance according to the value(s) in the table below.
      Fig 1: Checking For CAN Bus Wire (Main Wire For Disconnection, Bus Line For Short Circuit)
      GTY276444Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance

      Tester Connection Switch Condition Specified Condition resistance: Malfunction
      G43-40 (CA1P) - G43-18 (CA1N) Engine switch off 54 to 69 Ω Below 54 Ω: Short in line
      Higher than 69 Ω: Open in CAN main bus line
      G43-40 (CA1P) - G37-16 (BAT) Engine switch off 6 kΩ or higher Below 6 kΩ: +B short
      G43-18 (CA1N) - G37-16 (BAT) Engine switch off 6 kΩ or higher Below 6 kΩ: +B short
      G43-40 (CA1P) - G37-4 (CG) Engine switch off 200 Ω or higher Below 200 Ω: Ground short
      G43-18 (CA1N) - G37-4 (CG) Engine switch off 200 Ω or higher Below 200 Ω: Ground short
      TEXT IN ILLUSTRATION

      *a Component with harness connected
      (Driving Support ECU Assembly)
      RESULT

      Result Proceed to
      NG
      - Open in CAN main wire      		 A
      NG
      - Short in line
      - +B short
      - Ground short      		 B
      OK C

    B → See step   9 

    C → See step   21 

    A: Go to next step 

  3. CHECK FOR OPEN IN CAN BUS MAIN WIRE (NO. 3 JUNCTION CONNECTOR - DRIVING SUPPORT ECU) 
    1. Disconnect the G80 No. 3 junction connector connector.
      Fig 2: Identifying G80 No. 3 Junction Connector Terminals
      GTY279353Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Switch Condition Specified Condition
      G80-9 (CANH) - G80-20 (CANL) Engine switch off 108 to 132 Ω
      TEXT IN ILLUSTRATION

      *a Rear view of wire harness connector
      (to No. 3 Junction Connector)

    NG → See step   5 

    OK: Go to next step 

  4. CHECK FOR OPEN IN CAN BUS MAIN WIRE (NO. 3 JUNCTION CONNECTOR - MILLIMETER WAVE RADAR SENSOR) 
    1. Measure the resistance according to the value(s) in the table below.
      Fig 3: Checking For Open In CAN Bus Main Wire (No. 3 Junction Connector - Millimeter Wave Radar Sensor)
      GTY279363Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance

      Tester Connection Switch Condition Specified Condition
      G80-11 (CANH) - G80-22 (CANL) Engine switch off 108 to 132 Ω
      TEXT IN ILLUSTRATION

      *a Rear view of wire harness connector
      (to No. 3 Junction Connector)

    NG → See step   7 

    OK → REPAIR OR REPLACE NO. 3 JUNCTION CONNECTOR 

  5. CONNECT CONNECTOR 
    1. Reconnect the G80 No. 3 junction connector connector.

    NEXT: Go to next step 

  6. CHECK FOR OPEN IN CAN BUS MAIN WIRE (DRIVING SUPPORT ECU - NO. 3 JUNCTION CONNECTOR) 
    1. Disconnect the G43 driving support ECU assembly connector.
      Fig 4: Identifying G43 Driving Support ECU Assembly Connector Terminals
      GTY261499Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Switch Condition Specified Condition
      G43-40 (CA1P) - G43-18 (CA1N) Engine switch off 108 to 132 Ω
      TEXT IN ILLUSTRATION

      *a Rear view of wire harness connector
      (to Driving Support ECU Assembly)

    NG → REPAIR OR REPLACE CAN MAIN WIRE CONNECTED TO DRIVING SUPPORT ECU (DRIVING SUPPORT ECU - NO. 3 JUNCTION CONNECTOR) 

    OK → See step   26 

  7. CONNECT CONNECTOR 
    1. Reconnect the G80 No. 3 junction connector connector.

    NEXT: Go to next step 

  8. CHECK FOR OPEN IN CAN BUS MAIN WIRE (MILLIMETER WAVE RADAR SENSOR - NO. 3 JUNCTION CONNECTOR) 
    1. Disconnect the A12 millimeter wave radar sensor assembly connector.
      Fig 5: Identifying A12 Millimeter Wave Radar Sensor Assembly Connector Terminals
      GTY262021Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Switch Condition Specified Condition
      A12-4 (CA1P) - A12-3 (CA1N) Engine switch off 108 to 132 Ω
      TEXT IN ILLUSTRATION

      *a Front view of wire harness connector
      (to Millimeter Wave Radar Sensor Assembly)

    NG → REPAIR OR REPLACE CAN MAIN WIRE CONNECTED TO MILLIMETER WAVE RADAR SENSOR (MILLIMETER WAVE RADAR SENSOR - NO. 3 JUNCTION CONNECTOR) 

    OK → See step   23 

  9. CHECK FOR SHORT IN CAN BUS WIRES (NO. 3 JUNCTION CONNECTOR - LANE RECOGNITION CAMERA SENSOR) 

    HINT: 

    For vehicles without a lane departure alert system, go to "Check for Short in CAN Bus Wires (No. 3 Junction Connector - Driver Monitor ECU)".

    1. Disconnect the G80 No. 3 junction connector connector.
      Fig 6: Identifying G80 No. 3 Junction Connector Terminals
      GTY268104Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Switch Condition Specified Condition
      G80-10 (CANH) - G80-21 (CANL) Engine switch off 200 Ω or higher
      G80-10 (CANH) - G37-4 (CG) Engine switch off 200 Ω or higher
      G80-21 (CANL) - G37-4 (CG) Engine switch off 200 Ω or higher
      G80-10 (CANH) - G37-16 (BAT) Engine switch off 6 kΩ or higher
      G80-21 (CANL) - G37-16 (BAT) Engine switch off 6 kΩ or higher
      TEXT IN ILLUSTRATION

      *a Rear view of wire harness connector
      (to No. 3 Junction Connector)
      *b Front view of DLC3

    NG → See step   13 

    OK: Go to next step 

  10. CHECK FOR SHORT IN CAN BUS WIRES (NO. 3 JUNCTION CONNECTOR - DRIVER MONITOR ECU) 

    HINT: 

    For vehicles without a driver monitor camera, go to "Check for Short in CAN Bus Wires (No. 3 Junction Connector - Millimeter Wave Radar Sensor)".

    1. Measure the resistance according to the value(s) in the table below.
      Fig 7: Checking For Short In CAN Bus Wires (No. 3 Junction Connector - Driver Monitor ECU)
      GTY268101Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance

      Tester Connection Switch Condition Specified Condition
      G80-8 (CANH) - G80-19 (CANL) Engine switch off 200 Ω or higher
      G80-8 (CANH) - G37-4 (CG) Engine switch off 200 Ω or higher
      G80-19 (CANL) - G37-4 (CG) Engine switch off 200 Ω or higher
      G80-8 (CANH) - G37-16 (BAT) Engine switch off 6 kΩ or higher
      G80-19 (CANL) - G37-16 (BAT) Engine switch off 6 kΩ or higher
      TEXT IN ILLUSTRATION

      *a Rear view of wire harness connector
      (to No. 3 Junction Connector)
      *b Front view of DLC3

    NG → See step   15 

    OK: Go to next step 

  11. CHECK FOR SHORT IN CAN BUS WIRES (NO. 3 JUNCTION CONNECTOR - MILLIMETER WAVE RADAR SENSOR) 
    1. Measure the resistance according to the value(s) in the table below.
      Fig 8: Checking For Short In CAN Bus Wires (No. 3 Junction Connector - Millimeter Wave Radar Sensor)
      GTY284762Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance

      Tester Connection Switch Condition Specified Condition
      G80-11 (CANH) - G80-22 (CANL) Engine switch off 108 to 132 Ω
      G80-11 (CANH) - G37-4 (CG) Engine switch off 200 Ω or higher
      G80-22 (CANL) - G37-4 (CG) Engine switch off 200 Ω or higher
      G80-11 (CANH) - G37-16 (BAT) Engine switch off 6 kΩ or higher
      G80-22 (CANL) - G37-16 (BAT) Engine switch off 6 kΩ or higher
      TEXT IN ILLUSTRATION

      *a Rear view of wire harness connector
      (to No. 3 Junction Connector)
      *b Front view of DLC3

    NG → See step   17 

    OK: Go to next step 

  12. CHECK FOR SHORT IN CAN BUS WIRES (NO. 3 JUNCTION CONNECTOR - DRIVING SUPPORT ECU) 
    1. Measure the resistance according to the value(s) in the table below.
      Fig 9: Checking For Short In CAN Bus Wires (No. 3 Junction Connector - Driving Support ECU)
      GTY268103Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance

      Tester Connection Switch Condition Specified Condition
      G80-9 (CANH) - G80-20 (CANL) Engine switch off 108 to 132 Ω
      G80-9 (CANH) - G37-4 (CG) Engine switch off 200 Ω or higher
      G80-20 (CANL) - G37-4 (CG) Engine switch off 200 Ω or higher
      G80-9 (CANH) - G37-16 (BAT) Engine switch off 6 kΩ or higher
      G80-20 (CANL) - G37-16 (BAT) Engine switch off 6 kΩ or higher
      TEXT IN ILLUSTRATION

      *a Rear view of wire harness connector
      (to No. 3 Junction Connector)
      *b Front view of DLC3

    NG → See step   19 

    OK → REPAIR OR REPLACE NO. 3 JUNCTION CONNECTOR 

  13. CONNECT CONNECTOR 
    1. Reconnect the G80 No. 3 junction connector connector.

    NEXT: Go to next step 

  14. CHECK FOR SHORT IN CAN BUS WIRES (LANE RECOGNITION CAMERA SENSOR) 
    1. Disconnect the W12 lane recognition camera sensor assembly connector.
      Fig 10: Identifying W12 Lane Recognition Camera Sensor Assembly Connector Terminals
      GTY259683Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Switch Condition Specified Condition
      W12-1 (CA1P) - W12-2 (CA1N) Engine switch off 54 to 69 Ω
      W12-1 (CA1P) - G37-4 (CG) Engine switch off 200 Ω or higher
      W12-2 (CA1N) - G37-4 (CG) Engine switch off 200 Ω or higher
      W12-1 (CA1P) - G37-16 (BAT) Engine switch off 6 kΩ or higher
      W12-2 (CA1N) - G37-16 (BAT) Engine switch off 6 kΩ or higher
      TEXT IN ILLUSTRATION

      *a Rear view of wire harness connector
      (to Lane Recognition Camera Sensor Assembly)
      *b Front view of DLC3

    NG → REPAIR OR REPLACE LANE RECOGNITION CAMERA SENSOR CAN BRANCH WIRE OR CONNECTOR (CA1P, CA1N) 

    OK → See step   24 

  15. CONNECT CONNECTOR 
    1. Reconnect the G80 No. 3 junction connector connector.

    NEXT: Go to next step 

  16. CHECK FOR SHORT IN CAN BUS WIRES (DRIVER MONITOR ECU) 
    1. Disconnect the G62 driver monitor ECU assembly connector.
      Fig 11: Identifying G62 Driver Monitor ECU Assembly Connector Terminals
      GTY280065Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Switch Condition Specified Condition
      G62-9 (CANH) - G62-24 (CANL) Engine switch off 54 to 69 Ω
      G62-9 (CANH) - G37-4 (CG) Engine switch off 200 Ω or higher
      G62-24 (CANL) - G37-4 (CG) Engine switch off 200 Ω or higher
      G62-9 (CANH) - G37-16 (BAT) Engine switch off 6 kΩ or higher
      G62-24 (CANL) - G37-16 (BAT) Engine switch off 6 kΩ or higher
      TEXT IN ILLUSTRATION

      *a Rear view of wire harness connector
      (to Driver Monitor ECU Assembly)
      *b Front view of DLC3

    NG → REPAIR OR REPLACE DRIVER MONITOR ECU BRANCH WIRE OR CONNECTOR (CANH, CANL) 

    OK → See step   28 

  17. CONNECT CONNECTOR 
    1. Reconnect the G80 No. 3 junction connector connector.

    NEXT: Go to next step 

  18. CHECK FOR SHORT IN CAN BUS WIRES (MILLIMETER WAVE RADAR SENSOR) 
    1. Disconnect the A12 millimeter wave radar sensor assembly connector.
      Fig 12: Identifying A12 Millimeter Wave Radar Sensor Assembly Connector Terminals
      GTY257929Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Switch Condition Specified Condition
      A12-4 (CA1P) - A12-3 (CA1N) Engine switch off 108 to 132 Ω
      A12-4 (CA1P) - G37-4 (CG) Engine switch off 200 Ω or higher
      A12-3 (CA1N) - G37-4 (CG) Engine switch off 200 Ω or higher
      A12-4 (CA1P) - G37-16 (BAT) Engine switch off 6 kΩ or higher
      A12-3 (CA1N) - G37-16 (BAT) Engine switch off 6 kΩ or higher
      TEXT IN ILLUSTRATION

      *a Front view of wire harness connector
      (to Millimeter Wave Radar Sensor Assembly)
      *b Front view of DLC3

    NG → REPAIR OR REPLACE MILLIMETER WAVE RADAR SENSOR CAN MAIN WIRE OR CONNECTOR (CA1P, CA1N) 

    OK → See step   27 

  19. CONNECT CONNECTOR 
    1. Reconnect the G80 No. 3 junction connector connector.

    NEXT: Go to next step 

  20. CHECK FOR SHORT IN CAN BUS WIRES (DRIVING SUPPORT ECU) 
    1. Disconnect the G43 driving support ECU assembly connector.
      Fig 13: Identifying G43 Driving Support ECU Assembly Connector Terminals
      GTY255872Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Switch Condition Specified Condition
      G43-40 (CA1P) - G43-18 (CA1N) Engine switch off 108 to 132 Ω
      G43-40 (CA1P) - G37-4 (CG) Engine switch off 200 Ω or higher
      G43-18 (CA1N) - G37-4 (CG) Engine switch off 200 Ω or higher
      G43-40 (CA1P) - G37-16 (BAT) Engine switch off 6 kΩ or higher
      G43-18 (CA1N) - G37-16 (BAT) Engine switch off 6 kΩ or higher
      TEXT IN ILLUSTRATION

      *a Rear view of wire harness connector
      (to Driving Support ECU Assembly)
      *b Front view of DLC3

    NG → REPAIR OR REPLACE DRIVING SUPPORT ECU CAN MAIN WIRE OR CONNECTOR (CA1P, CA1N) 

    OK → See step   25 

  21. CHECK HARNESS AND CONNECTOR (DRIVING SUPPORT ECU - BATTERY AND GROUND) 
    1. Connect the cable to the negative (-) battery terminal.
      Fig 14: Identifying G43 Driving Support ECU Assembly Connector Terminals
      GTY276086Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      NOTE:

      When disconnecting the cable, some systems need to be initialized after the cable is reconnected. Refer to INITIALIZATION .

    2. Disconnect the G43 driving support ECU assembly connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G43-25 (GND) - Body ground Always Below 1 Ω
    4. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      G43-30 (B) - Body ground Engine switch on (IG) 11 to 14 V
      TEXT IN ILLUSTRATION

      *a Rear view of wire harness connector
      (to Driving Support ECU Assembly)

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → See step   22 

  22. REPLACE DRIVING SUPPORT ECU ASSEMBLY. Refer to  REMOVAL 
  23. REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY. Refer to  REMOVAL 
  24. REPLACE LANE RECOGNITION CAMERA SENSOR ASSEMBLY. Refer to  REMOVAL 
  25. REPLACE DRIVING SUPPORT ECU ASSEMBLY. Refer to  REMOVAL 
  26. REPLACE DRIVING SUPPORT ECU ASSEMBLY. Refer to  REMOVAL 
  27. REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY. Refer to  REMOVAL 
  28. REPLACE DRIVER MONITOR ECU ASSEMBLY. Refer to  REMOVAL 
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