ANTI-LOCK 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 GTS.


    1. Turn the ignition switch off.

    2. Connect the GTS to the DLC3.

    3. Turn the ignition switch to ON.

    4. Turn the GTS on.

    5. Follow the directions on the GTS 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 ignition switch is turned to ON (initial check).

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

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


      Chassis > ABS/VSC/TRC > Data List
      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      FR Speed Open Front speed sensor RH open detection Error or Normal Normal Error: Momentary interruption
      FL Speed Open Front speed sensor LH open detection Error or Normal Normal Error: Momentary interruption
      RR Speed Open Rear speed sensor RH open detection Error or Normal Normal Error: Momentary interruption
      RL Speed Open Rear speed sensor LH open detection Error or Normal Normal Error: Momentary interruption
      EFI Communication Open ECM communication open detection Error or Normal Normal Error: Momentary interruption
      Deceleration Open Deceleration sensor open detection Error or Normal Normal Error: Momentary interruption
      IG Voltage Value Decreased IG voltage value decrease detection Error or Normal Normal Error: Voltage low
      IG Voltage Value Increased IG voltage value increase detection Error or Normal Normal Error: Voltage high
      FR Speed Sensor Voltage Open Front speed sensor RH voltage open detection Error or Normal Normal Error: Momentary interruption
      FL Speed Sensor Voltage Open Front speed sensor LH voltage open detection Error or Normal Normal Error: Momentary interruption
      RR Speed Sensor Voltage Open Rear speed sensor RH voltage open detection Error or Normal Normal Error: Momentary interruption
      RL Speed Sensor Voltage Open Rear speed sensor LH voltage open detection Error or Normal Normal Error: Momentary interruption
      EFI Communication Invalid ECM communication invalid detection Error or Normal Normal Error: Invalid

    6. 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.