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 harness between the sensors and ECUs can be detected in the ECU Data List function of the intelligent tester.


    1. Turn the power switch OFF and connect the intelligent tester to the DLC3.

    2. Turn the power switch ON (IG). Follow the directions on the intelligent tester to display the Data List and select areas where momentary interruptions are monitored.

      Tech Tips

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

      ABS/VSC/TRAC:
      Item (Display)

      Measurement Item /

      Range (Display)

      		 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

      		 -
      HV Communication Open HV 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 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 Cylinder2 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 Front wheel cylinder pressure sensor RH open detection / ERROR or NORMAL

      ERROR: Momentary interruption

      NORMAL: Normal

      		 -
      FL Wheel Cylinder Open Front wheel cylinder pressure sensor LH open detection / ERROR or NORMAL

      ERROR: Momentary interruption

      NORMAL: Normal

      		 -
      RR Wheel Cylinder Open Rear wheel cylinder pressure sensor RH open detection / ERROR or NORMAL

      ERROR: Momentary interruption

      NORMAL: Normal

      		 -
      RL Wheel Cylinder open Rear wheel cylinder pressure sensor LH 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

      		 -

      Tech Tips


      • If the ERROR display remains on, check the continuity between the ECU and the sensors, or between ECUs.

      • The ERROR display 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.

      Tech Tips

      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.