ELECTRONICALLY CONTROLLED BRAKE SYSTEM CHECK FOR INTERMITTENT PROBLEMS


  1. CHECK FOR INTERMITTENT PROBLEMS

    Tech Tips

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


    1. Turn the power switch off.

    2. Connect the intelligent tester to the DLC3.

    3. Turn the power switch on (IG).

    4. Turn the intelligent tester on.

    5. Follow the directions on the intelligent tester to display the Data List and select areas where momentary interruptions should be monitored.

      Tech Tips


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

      • If the Error display remains displayed, check for continuity between the ECUs and the sensors, or between ECUs.

      • The Error display on the intelligent tester will remain displayed for 1 second after the harness signal changes from momentary interruption (open circuit) to normal condition.

      ABS/VSC/TRC
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      FR Speed Open Front speed sensor RH open detection / Error or Normal

      Error: Momentary interruption

      Normal: Normal

      		 -
      FL Speed Open Front speed sensor LH open detection / Error or Normal

      Error: Momentary interruption

      Normal: Normal

      		 -
      RR Speed Open Rear speed sensor RH open detection / Error or Normal

      Error: Momentary interruption

      Normal: Normal

      		 -
      RL Speed Open Rear speed sensor LH 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

      		 -
      Master Cylinder Open Regulator pressure sensor open detection / Error or Normal

      Error: Momentary interruption

      Normal: Normal

      		 -
      Stroke Open Brake pedal stroke sensor open detection / Error or Normal

      Error: Momentary interruption

      Normal: Normal

      		 -
      FR Wheel Cylinder Open 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 Hybrid vehicle communication open detection / Error or Normal

      Error: Momentary interruption

      Normal: Normal

      		 -

    6. While observing the screen, gently jiggle the connectors or wire harnesses between the ECUs and sensors, or between ECUs.

      Tech Tips

      If the display changes, this indicates that there has been a momentary interruption (open circuit) in the connector and/or wire harness. In this case, repair or replace the connectors and/or wire harnesses as one of them is faulty.