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Check For Intermittent Problems

WARNING: This page is about a different car, the 2008 Toyota Yaris. However, it is still accessible from the selected car via links, so may be relevant.
  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 by using the ECU data list function of a Techstream.

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

      HINT:

      • A momentary interruption (open circuit) cannot be detected for 3 seconds after the ignition switch is turned to ON (initial check).
      • If the status remains on the ERROR display, check for continuity between the ECU and the sensors, or between ECUs.
      • The ERROR display on the Techstream remains on for 1 second after the harness signal changes from a momentary interruption (open circuit) to normal condition.
        Fig 1: Harness Signal And Tester Display Blinking Pattern
        G05591530Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
        DATA LIST 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
        -
    4. While observing the screen, gently jiggle the connector or wire harness between the ECU and sensors, or between ECUs.

      OK: 

      Display does not change. 

      HINT:

      The connector and/or wire harness have a momentary interruption (open circuit) if the display changes. Repair or replace the connector and wire harness if either of them is faulty.

      Fig 2: Jiggling Connector Or Wire Harness Between ECU And Sensors
      G04832151Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002