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Home >> Scion >> 2016 >> iM Automatic CVT Trans >> Repair and Diagnosis (Single Page) >> Brakes >> Traction Control >> Vehicle Stability Control System - (Diagnostic Codes & Symptom Tests) >> Vehicle Stability Control System >> DTC U0073: Control Module Communication Bus OFF; DTC U0100: Lost Communication with ECM; DTC U0124: Lost Communication with Lateral Acceleration Sensor Module; DTC U0126: Lost Communication with Steering Angle Sensor Module [06/2015 - ] >> Procedure
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DTC U0073: Control Module Communication Bus OFF; DTC U0100: Lost Communication with ECM; DTC U0124: Lost Communication with Lateral Acceleration Sensor Module; DTC U0126: Lost Communication with Steering Angle Sensor Module [06/2015 - ]: Procedure

  1. CHECK HARNESS AND CONNECTOR (MOMENTARY INTERRUPTION) 
    1. Using the Techstream, check for any momentary interruption in the wire harness and connector corresponding to a DTC.

      Refer to CHECK FOR INTERMITTENT PROBLEMS [06/2015 - ]

      Chassis > ABS/VSC/TRAC > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      EFI Communication Open ECM communication open detection Error or Normal Error: Momentary interruption
      Normal: Normal      		 -
      Yaw Rate Open Yaw rate sensor open detection Error or Normal Error: Momentary interruption
      Normal: Normal      		 -
      Deceleration Open Acceleration sensor open detection Error or Normal Error: Momentary interruption
      Normal: Normal      		 -
      Steering Open Steering angle sensor open detection Error or Normal Error: Momentary interruption
      Normal: Normal      		 -

      Chassis > ABS/VSC/TRAC > Data List 

      Tester Display
      EFI Communication Open
      Yaw Rate Open
      Deceleration Open
      Steering Open

      Result

      Result Proceed to
      There is a constant open circuit. A
      There are no momentary interruptions. B
      There are momentary interruptions. C

      HINT: 

      Perform the above inspection before removing the sensor and connector.

    Result:  2

    B 

    See step  3

    Result:  3

    C 

    See step  4

    Result:  1

    A 

    See step  2

  2. CHECK IF EACH CONNECTOR IS SECURELY CONNECTED (ECM, SENSOR, AIRBAG SENSOR ASSEMBLY) 
    1. Turn the ignition switch off.
    2. Check if each sensor, ECM, and yaw rate and acceleration sensor (airbag sensor assembly) connector is securely connected.

      OK

      Each connector is securely connected.

      Result

      Proceed to
      OK
      NG

    Result:  2

    NG 

    CONNECT CONNECTOR TO EACH SENSOR, ECM, AND AIRBAG SENSOR ASSEMBLY CORRECTLY 

    Result:  1

    OK 

    See step  3

  3. RECONFIRM DTC 
    1. Turn the ignition switch off.
    2. Record the output DTCs (for VSC system and/or CAN communication system).

      for VSC system: Refer to DTC CHECK / CLEAR [06/2015 - ]

      for CAN communication system: Refer to DIAGNOSIS SYSTEM [06/2015 - ]

      Chassis > ABS/VSC/TRAC > Trouble Codes 

      HINT: 

      If the CAN communication system DTC and the relevant sensor DTCs are output simultaneously, troubleshoot the relevant sensor DTCs (for VSC system) after the CAN communication system returns to normal.

      Result

      Result Proceed to
      DTCs (relating to CAN communication system) are output. A
      DTCs (relating to VSC system) are output. B
      DTCs are not output. C

    Result:  1

    A 

    CHECK CAN COMMUNICATION SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [06/2015 - ] 

    Result:  2

    B 

    REPAIR CIRCUIT INDICATED BY OUTPUT DTCS. Refer to  DIAGNOSTIC TROUBLE CODE CHART [06/2015 - ] 

    Result:  3

    C 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [06/2015 - ] 

  4. REPAIR OR REPLACE HARNESS OR CONNECTOR 
    1. Turn the ignition switch off.
    2. Repair or replace the harness or connector.
    3. Check for any momentary interruption between the skid control ECU (brake actuator assembly) and each sensor, ECM, and yaw rate and acceleration sensor (airbag sensor assembly).

      Refer to CHECK FOR INTERMITTENT PROBLEMS [06/2015 - ]

    4. Check that there is no momentary interruption.

      Result

      Proceed to
      NEXT

    Result:  1

    NEXT 

    See step  5

  5. RECONFIRM DTC 
    1. Turn the ignition switch off.
    2. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [06/2015 - ]

      Chassis > ABS/VSC/TRAC > Clear DTCs 

    3. Turn the ignition switch off.
    4. Start the engine.
    5. Drive the vehicle at a speed of 15 km/h (9 mph) or more and turn the steering wheel to the right and left.
    6. Check that no CAN communication system DTC is output.

      Refer to DIAGNOSIS SYSTEM [06/2015 - ]

    7. If VSC system DTCs are output, record them.

      Refer to DTC CHECK / CLEAR [06/2015 - ]

      Chassis > ABS/VSC/TRAC > Trouble Codes 

      Result

      Result Proceed to
      DTCs are not output. A
      DTCs are output (relating to VSC system). B
      DTCs are output (relating to CAN communication system). C

      HINT: 

      The CAN communication system must be normal when repairing each sensor DTC (for VSC system).

    Result:  1

    A 

    END 

    Result:  2

    B 

    REPAIR CIRCUIT INDICATED BY OUTPUT DTCS. Refer to  DIAGNOSTIC TROUBLE CODE CHART [06/2015 - ] 

    Result:  3

    C 

    CHECK CAN COMMUNICATION SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [06/2015 - ] 

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