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Home >> Lexus >> 2015 >> ES 300h >> Repair and Diagnosis (Single Page) >> Brakes >> Anti-Lock Brakes >> Electronically Controlled Brake System (Diagnostic Codes & Symptom Tests) >> Electronically Controlled Brake System >> DTC U0073/94: Control Module Communication Bus OFF; DTC U0123/62: Lost Communication with Yaw Rate Sensor Module; DTC U0124/95: Lost Communication with Lateral Acceleration Sensor Module; DTC U0126/63: Lost Communication with Steering Angle Sensor Module; DTC U0293/59: Communication Error from HV ECU [08/2014 - ] >> Procedure
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DTC U0073/94: Control Module Communication Bus OFF; DTC U0123/62: Lost Communication with Yaw Rate Sensor Module; DTC U0124/95: Lost Communication with Lateral Acceleration Sensor Module; DTC U0126/63: Lost Communication with Steering Angle Sensor Module; DTC U0293/59: Communication Error from HV ECU [08/2014 - ]: Procedure

  1. CHECK HARNESS AND CONNECTOR (MOMENTARY INTERRUPTION) 
    1. Using the Techstream, check for any momentary interruptions 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
      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
      -
      HV Communication Open Hybrid vehicle communication open detection / Error or Normal Error: Momentary interruption
      Normal: Normal
      -

      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 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 (POWER MANAGEMENT CONTROL ECU, SENSOR) 
    1. Turn the power switch off.
    2. Check if each sensor and ECU connector is securely connected.

      OK

      Each sensor and ECU connector is securely connected.

    NG → CONNECT CONNECTOR TO EACH SENSOR OR ECU CORRECTLY 

    OK: Go to next step 

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

      HINT: 

      If CAN communication system DTCs and relevant sensor DTCs are output simultaneously, troubleshoot the relevant sensor DTCs (for ABS, VSC and/or electronically controlled brake system) after the CAN communication system returns to normal.

      Result

      Result Proceed to
      DTCs are not output. A
      ABS, VSC and/or electronically controlled brake system 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 power switch off.
    2. Repair or replace the harness or connector.
    3. Check for any momentary interruptions between the skid control ECU (brake booster with master cylinder assembly) and each sensor or ECU. Refer to CHECK FOR INTERMITTENT PROBLEMS [08/2014 - ] .

    NEXT: Go to next step 

  5. RECONFIRM DTC 
    1. Turn the power switch off.
    2. Clear the DTCs. Refer to DTC CHECK / CLEAR [08/2014 - ] .
    3. Turn the power switch on (READY).
    4. Drive the vehicle at a speed of 15 km/h (9 mph) or more and turn the steering wheel to the right and left.
    5. Check that no CAN communication system DTCs are output. Refer to DIAGNOSIS SYSTEM [08/2014 - ] .
    6. If ABS, VSC and/or electronically controlled brake system DTCs are output, record them. Refer to DTC CHECK / CLEAR [08/2014 - ] .

      Result

      Result Proceed to
      DTCs are not output. A
      ABS, VSC and/or electronically controlled brake system 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 ABS, VSC and/or electronically controlled brake 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 - ]