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Check For Intermittent Problems

  1. CHECK FOR INTERMITTENT PROBLEMS 

    HINT:

    A momentary interruption (open circuit) in the connectors and/or wire harness between the sensors and ECUs can be detected in the ECU Data List function of Techstream.

    1. Turn the ignition switch off and connect Techstream to the DLC3.
    2. Turn the ignition switch on. Follow the directions on Techstream to display the Data List and select areas where momentary interruption should be monitored.

      HINT:

      A momentary interruption (open circuit) cannot be detected for 3 seconds after the ignition switch is turned on (initial check).

      Fig 1: Momentary Interruption Harness Signal
      G05859582Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      ABS / VSC / TRAC: 

      ABS / VSC / TRAC INTERMITTENT PROBLEMS REFERENCE

      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      FR Speed Open FR speed sensor open detection / ERROR or NORMAL ERROR: Momentary interruption
      NORMAL: Normal
      -
      FL Speed Open FL speed sensor open detection / ERROR or NORMAL ERROR: Momentary interruption
      NORMAL: Normal
      -
      RR Speed Open RR speed sensor open detection / ERROR or NORMAL ERROR: Momentary interruption
      NORMAL: Normal
      -
      RL Speed Open RL speed sensor 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 Deceleration 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
      -
      Master Cylinder Open Master Cylinder pressure sensor open detection / ERROR or NORMAL ERROR: Momentary interruption
      NORMAL: Normal
      -
      Master Cylinder 2 Open Master Cylinder pressure sensor 2 open detection / ERROR or NORMAL ERROR: Momentary interruption
      NORMAL: Normal
      -
      Stroke Open Stroke sensor open detection / ERROR or NORMAL ERROR: Momentary interruption
      NORMAL: Normal
      -
      FR Wheel Cylinder Open FR wheel cylinder pressure sensor open detection / ERROR or NORMAL ERROR: Momentary interruption
      NORMAL: Normal
      -
      FL Wheel Cylinder Open FL wheel cylinder pressure sensor open detection / ERROR or NORMAL ERROR: Momentary interruption
      NORMAL: Normal
      -
      RR Wheel Cylinder Open RR wheel cylinder pressure sensor open detection / ERROR or NORMAL ERROR: Momentary interruption
      NORMAL: Normal
      -
      RL Wheel Cylinder Open RL wheel cylinder pressure sensor open detection / ERROR or NORMAL ERROR: Momentary interruption
      NORMAL: Normal
      -
      Accumulator Open Accumulator pressure sensor open detection / ERROR or NORMAL ERROR: Momentary interruption
      NORMAL: Normal
      -
      HV Communication Open HV communication open detection / ERROR or NORMAL ERROR: Momentary interruption
      NORMAL: Normal
      -

      HINT:

      • If the status remains on (ERROR displayed), check the continuity between the ECU and the sensors, or between ECUs.
      • The ERROR display on Techstream remains on for 1 second after the harness signal changes from momentary interruption (open circuit) to normal condition.
    3. While observing the screen, gently jiggle the connector or wire harness between the ECU and sensors, or between ECUs.

      Result: 

      ERROR display does not change. 

      HINT:

      The connector and/or wire harness will be in momentary interruption (open circuit) if the display changes. Repair or replace connector and/or wire harness as one of them is faulty.

      Fig 2: Checking Connectors
      G04832151Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002