VEHICLE STABILITY CONTROL SYSTEM (for Vacuum Brake Booster) 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 ignition switch off.

    2. Connect the intelligent tester to the DLC3.

    3. Turn the ignition switch to ON.

    4. Turn the intelligent tester on.

    5. Enter the following menus: Chassis / ABS/VSC/TRC / Data List.

    6. Select areas where momentary interruptions should be monitored.

      Tech Tips


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

      • If Error is displayed, measure the resistance between the ECUs and sensors or between ECUs.

      • Error remains displayed on the intelligent tester for 1 second after the harness signal changes from a momentary interruption (open circuit) to normal.

      ABS/VSC/TRC
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      FR Speed Open Front speed sensor RH open circuit detection/ Error or Normal Normal -
      FL Speed Open Front speed sensor LH open circuit detection/ Error or Normal Normal -
      RR Speed Open Rear speed sensor RH open circuit detection/ Error or Normal Normal -
      RL Speed Open Rear speed sensor LH open circuit detection/ Error or Normal Normal -
      EFI Communication Open ECM communication open circuit detection/ Error or Normal Normal -
      Yaw Rate Open Yaw rate sensor open circuit detection/ Error or Normal Normal -
      Deceleration Open Acceleration sensor open circuit detection/ Error or Normal Normal -
      Steering Open Steering angle sensor open circuit detection/ Error or Normal Normal -
      Master Cylinder Open Master cylinder pressure sensor open circuit detection/ Error or Normal Normal -
      IG Voltage Value Decreased IG voltage value decrease detection/ Error or Normal Normal -
      IG Voltage Value Increased IG voltage value increase detection/ Error or Normal Normal -
      FR Speed Sensor Voltage Open Front speed sensor RH voltage open circuit detection/ Error or Normal Normal -
      FL Speed Sensor Voltage Open Front speed sensor LH voltage open circuit detection/ Error or Normal Normal -
      RR Speed Sensor Voltage Open Rear speed sensor RH voltage open circuit detection/ Error or Normal Normal -
      RL Speed Sensor Voltage Open Rear speed sensor LH voltage open circuit detection/ Error or Normal Normal -
      M/C Pressure Sensor Noise Master cylinder pressure sensor noise detection/ Error or Normal Normal -
      Brake Pedal Switch Open Brake pedal load sensing switch open circuit detection/ Error or Normal Normal -
      Yaw Rate Sensor Voltage Open Yaw rate sensor voltage open circuit detection/ Error or Normal Normal -
      EFI Communication Invalid ECM communication invalid detection/ Error or Normal Normal -

    7. While observing the screen, gently jiggle the connector or wire harness between the ECU and sensors or between ECUs.

      Tech Tips

      If the display changes, the connector and/or the wire harness has caused a momentary interruption of the circuit. Repair or replace the connector and/or wire harness as one of them is faulty.