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Home >> Toyota >> 2012 >> Prius Three >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Collision/Avoidance >> Lane Keeping Assist System (Except Plug-In) (Diagnostic Codes & Circuit Tests) >> Lane-Keeping Assist System >> DTC U0122: Lost Communication with Vehicle Dynamics Control Module; DTC U0123: Lost Communication with Yaw Rate Sensor Module; DTC U0131: Lost Communication with Power Steering Control Module; DTC U1104: Lost Communication with Driving Support ECU >> Procedure
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DTC U0122: Lost Communication with Vehicle Dynamics Control Module; DTC U0123: Lost Communication with Yaw Rate Sensor Module; DTC U0131: Lost Communication with Power Steering Control Module; DTC U1104: Lost Communication with Driving Support ECU: Procedure

  1. CHECK DTC OUTPUT 
    1. Using the Techstream, enter the following menus: All ECUs / Lane Keeping Assist / Trouble Codes.
    2. Check for DTCs. Refer to DTC CHECK / CLEAR .

      Result

      Result Proceed to
      DTC U1104 is output A
      DTC other than U1104 is output B

    B → See step   7 

    A: Go to next step 

  2. CHECK CAN COMMUNICATION SYSTEM 
    1. Select "CAN Bus Check" from the "System Selection Menu" screen on the Techstream.
    2. Select "Communication Malfunction DTC" from the "CAN Bus Check" screen, and then select "Enter".

      OK

      CAN communication is normal.

    NG → See step   7 

    OK: Go to next step 

  3. CHECK HARNESS AND CONNECTOR (LANE RECOGNITION CAMERA SENSOR ASSEMBLY POWER SOURCE) 
    1. Disconnect the lane recognition camera sensor assembly connector.
      Fig 1: Identifying Lane Recognition Camera Sensor Assembly Connector Terminals
      GTY226544Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Turn the power switch on (IG).
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      U4-8 (IGB) - Body ground Power switch on (IG) 10 to 14 V
      TEXT IN ILLUSTRATION

      *1 Front view of wire harness connector
      (to Lane Recognition Camera Sensor Assembly)
    4. Reconnect the recognition camera sensor connector.

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

    OK: Go to next step 

  4. CHECK HARNESS AND CONNECTOR (LANE RECOGNITION CAMERA SENSOR ASSEMBLY GND CIRCUIT) 
    1. Disconnect the lane recognition camera sensor assembly connector.
      Fig 2: Identifying Lane Recognition Camera Sensor Assembly Connector Terminals
      GTY226543Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for Open)

      Tester Connection Condition Specified Condition
      U4-4 (GND) - Body ground Always Below 1 Ω
      TEXT IN ILLUSTRATION

      *1 Front view of wire harness connector
      (to Lane Recognition Camera Sensor Assembly)

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

    OK: Go to next step 

  5. REPLACE LANE RECOGNITION CAMERA SENSOR ASSEMBLY 
    1. Replace the lane recognition camera sensor assembly. Refer to REMOVAL .
    2. Adjust the lane recognition camera assembly. Refer to ADJUSTMENT .

    NEXT: Go to next step 

  6. CHECK DTC OUTPUT 
    1. Using the Techstream, enter the following menus: All ECUs / Lane Keeping Assist / Trouble Codes.
    2. Clear the DTCs. Refer to DTC CHECK / CLEAR .
    3. Turn the power switch off.
    4. Turn the power switch on (IG).
    5. Drive the vehicle and operate lane keeping assist control.
    6. Recheck for DTCs.

      OK

      DTC is not output.

    NG → See step   8 

    OK → END 

  7. GO TO CAN COMMUNICATION CIRCUIT. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING 
  8. REPLACE DRIVING SUPPORT ECU. Refer to  REMOVAL 
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