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Home >> Toyota >> 2014 >> Sienna Base >> Repair and Diagnosis (Single Page) >> Restraints >> Air Bag, SRS >> Pre-Collision System (Diagnostic Codes & Circuit Tests) >> Pre-Collision System >> DTC U0122: Lost Communication with Vehicle Dynamics Control Module; DTC U0123: Lost Communication with Yaw Rate Sensor Module; DTC U0126: Lost Communication with Steering Angle Sensor Module; DTC U0140: Lost Communication with Main Body ECU; DTC U0151: Lost Communication with Airbag ECU; DTC U0235: Lost Communication with Cruise Control Front Distance Range Sensor; DTC U1100: Lost Communication with Seat Belt Control ECU; DTC U1104: Lost Communication with Driving Support ECU [08/2013 - ] >> Procedure
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DTC U0122: Lost Communication with Vehicle Dynamics Control Module; DTC U0123: Lost Communication with Yaw Rate Sensor Module; DTC U0126: Lost Communication with Steering Angle Sensor Module; DTC U0140: Lost Communication with Main Body ECU; DTC U0151: Lost Communication with Airbag ECU; DTC U0235: Lost Communication with Cruise Control Front Distance Range Sensor; DTC U1100: Lost Communication with Seat Belt Control ECU; DTC U1104: Lost Communication with Driving Support ECU [08/2013 - ]: Procedure

  1. CHECK FOR DTC 
    1. Connect the Techstream to the DLC3.
    2. Turn the ignition switch to ON.
    3. Turn the Techstream on.
    4. Enter the following menus: Body Electrical / Pre-Collision and Pre-Collision 2 / Trouble Codes.
    5. Check for DTCs.
      RESULT

      Result Proceed to
      DTC U1104 is output A
      DTC U1104 is not output B

    B → See step   8 

    A: Go to next step 

  2. CHECK HARNESS AND CONNECTOR (DRIVING SUPPORT ECU - MILLIMETER WAVE RADAR SENSOR) 
    1. Disconnect the A44 driving support ECU and A36 millimeter wave radar sensor connectors.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A44-38 (LRRD) - A36-4 (LRRD) Always Below 1 Ω
      A36-4 (LRRD) - Body ground Always 10 kΩ or higher
      A44-38 (LRRD) - Body ground Always 10 kΩ or higher
    3. Reconnect the driving support ECU and millimeter wave radar sensor connectors.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  3. CHECK MILLIMETER WAVE RADAR SENSOR (IGB VOLTAGE) 
    1. Disconnect the A36 millimeter wave radar sensor connector.
      GTY297845Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Turn the ignition switch to ON.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      A36-5 (IGB) - Body ground Ignition switch ON 11 to 14 V
      TEXT IN ILLUSTRATION

      *1 Front view of wire harness connector
      (to Millimeter Wave Radar Sensor)
    4. Reconnect the millimeter wave radar sensor connector.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (IGB CIRCUIT) 

    OK: Go to next step 

  4. CHECK MILLIMETER WAVE RADAR SENSOR (SGND CIRCUIT) 
    1. Disconnect the A36 millimeter wave radar sensor connector.
      GTY297846Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A36-2 (SGND) - Body ground Always Below 1 Ω
      TEXT IN ILLUSTRATION

      *1 Front view of wire harness connector
      (to Millimeter Wave Radar Sensor)
    3. Reconnect the millimeter wave radar sensor connector.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (SGND CIRCUIT) 

    OK: Go to next step 

  5. INSPECT DRIVING SUPPORT ECU (LRRD OUTPUT VOLTAGE) 
    1. Turn the ignition switch to ON.
      GTY302034Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      A44-38 (LRRD) - Body ground Ignition switch ON 4.5 to 5.5 V
      TEXT IN ILLUSTRATION

      *1 Component with harness connected
      (Driving Support ECU)

    NG → See step   9 

    OK: Go to next step 

  6. REPLACE MILLIMETER WAVE RADAR SENSOR 
    1. Replace the millimeter wave radar sensor. Refer to REMOVAL [08/2013 - ] .
    2. Adjust the millimeter wave radar sensor. Refer to ADJUSTMENT [08/2013 - ] .

    NEXT: Go to next step 

  7. CHECK FOR DTC 
    1. Clear the DTCs. Refer to DTC CHECK / CLEAR [08/2013 - ] .
    2. Check for DTCs. Refer to DTC CHECK / CLEAR [08/2013 - ] .
      RESULT

      Result Proceed to
      DTC U1104 is not output A
      DTC U1104 is output B

    B → See step   9 

    A → END 

  8. GO TO CAN COMMUNICATION SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2013 - ] 
  9. REPLACE DRIVING SUPPORT ECU. Refer to  REMOVAL [08/2013 - ]