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Home >> Lexus >> 2015 >> ES 350 >> Repair and Diagnosis >> Brakes >> Traction Control >> Vehicle Stability Control System - Diagnostics Codes & Symptom Tests >> Vehicle Stability Control System >> DTC U0073: Control Module Communication Bus OFF; DTC U0100: Lost Communication with ECM / PCM; DTC U0124: Lost Communication with Lateral Acceleration Sensor Module; DTC U0126: Lost Communication with Steering Angle Sensor Module [08/2014 - ] >> Procedure
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DTC U0073: Control Module Communication Bus OFF; DTC U0100: Lost Communication with ECM / PCM; DTC U0124: Lost Communication with Lateral Acceleration Sensor Module; DTC U0126: Lost Communication with Steering Angle Sensor Module [08/2014 - ]: 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 [08/2014 - ] .
      ABS/VSC/TRAC

      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
      -

      Result

      Result Proceed to
      There is a constant interruption. (Error is displayed without interruption.) A
      There are no momentary interruptions. B
      There are momentary interruptions. (Error is displayed intermittently.) C

      HINT: 

      Perform the above inspection before disconnecting any sensors or connectors.

    B → See step   3 

    C → See step   4 

    A: Go to next step 

  2. CHECK IF EACH CONNECTOR IS SECURELY CONNECTED (ECM, SENSOR) 
    1. Turn the engine switch off.
    2. Check if each sensor or ECM connector is securely connected.

      OK

      Each connector is securely connected.

    NG → CONNECT CONNECTOR TO EACH SENSOR OR ECM CORRECTLY 

    OK: Go to next step 

  3. RECONFIRM DTC 
    1. Turn the engine switch off.
    2. Record the output DTCs (for VSC system and/or CAN communication system). Refer to DTC CHECK / CLEAR [08/2014 - ] for VSC system, or. Refer to DIAGNOSIS SYSTEM [08/2014 - ] for CAN communication system).

      HINT: 

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

      Result

      Result Proceed to
      DTCs are not output. A
      DTCs are output. B
      CAN communication system DTCs are output. C

    B → See step   7 

    C → See step   6 

    A → See step   8 

  4. REPAIR OR REPLACE HARNESS OR CONNECTOR 
    1. Turn the engine switch off.
    2. Repair or replace the harness or connector.
    3. Check for any momentary interruptions between the skid control ECU (brake actuator assembly) and each sensor or ECM. Refer to CHECK FOR INTERMITTENT PROBLEMS [08/2014 - ] .

    NEXT: Go to next step 

  5. RECONFIRM DTC 
    1. Turn the engine switch off.
    2. Clear the DTCs. Refer to DTC CHECK / CLEAR [08/2014 - ] .
    3. Turn the engine 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 DTCs are output. Refer to DIAGNOSIS SYSTEM [08/2014 - ] .
    7. If VSC system DTCs are output, record them. Refer to DTC CHECK / CLEAR [08/2014 - ] .

      Result

      Result Proceed to
      DTCs are not output. A
      DTCs are output. B
      CAN communication system DTCs are output. C

      HINT: 

      The CAN communication system must be normal when performing troubleshooting for sensor DTCs (for VSC system).

    B → See step   7 

    C → See step   6 

    A → END 

  6. INSPECT CAN COMMUNICATION SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2014 - ] 
  7. REPAIR CIRCUITS INDICATED BY OUTPUT DTCS. Refer to  DIAGNOSTIC TROUBLE CODE CHART [08/2014 - ] 
  8. USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2014 - ]