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 in the ECU DATA LIST function of the Intelligent tester or Techstream.

1. Turn the power switch OFF and connect the Intelligent tester or Techstream to the DLC3.
2. Turn the power switch ON (IG). Follow the directions on the Intelligent tester or Techstream to display the DATA LIST and select areas where momentary interruptions are monitored.

   HINT:

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

   1. Intelligent tester
      Fig 1: Momentary Interruption - Blinking Pattern

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      ABS/VSC/TR(A)C: 

      ABS/VSC/TR(A)C REFERENCE
      
      

      Item (Display)	Measurement Item / Range (Display)	Normal Condition
      FR SPD OPN	Front speed sensor RH open detection / ERROR or NORMAL	ERROR Momentary interruption NORMAL Normal
      FL SPD OPN	Front speed sensor LH open detection / ERROR or NORMAL	ERROR Momentary interruption NORMAL Normal
      RR SPD OPN	Rear speed sensor RH open detection / ERROR or NORMAL	ERROR Momentary interruption NORMAL Normal
      RL SPD OPN	Rear speed sensor LH open detection / ERROR or NORMAL	ERROR Momentary interruption NORMAL Normal
      HV COM OPN	HV communication open detection / ERROR or NORMAL	ERROR Momentary interruption NORMAL Normal
      YAW RATE OPN	Yaw rate sensor open detection / ERROR or NORMAL	ERROR Momentary interruption NORMAL Normal
      DECELERAT OPN	Deceleration sensor open detection / ERROR or NORMAL	ERROR Momentary interruption NORMAL Normal
      STEERING OPN	Steering angle sensor open detection / ERROR or NORMAL	ERROR Momentary interruption NORMAL Normal
      M/C OPN	Master cylinder pressure sensor open detection / ERROR or NORMAL	ERROR Momentary interruption NORMAL Normal
      M/C2OPN	Master cylinder pressure sensor 2 open detection / ERROR or NORMAL	ERROR Momentary interruption NORMAL Normal
      STROKE OPN	Stroke sensor open detection / ERROR or NORMAL	ERROR Momentary interruption NORMAL Normal
      FR W/C OPN	Front wheel cylinder pressure sensor RH open detection / ERROR or NORMAL	ERROR Momentary interruption NORMAL Normal
      FL W/C OPN	Front wheel cylinder pressure sensor LH open detection / ERROR or NORMAL	ERROR Momentary interruption NORMAL Normal
      RR W/C OPN	Rear wheel cylinder pressure sensor RH open detection / ERROR or NORMAL	ERROR Momentary interruption NORMAL Normal
      RL W/C OPN	Rear wheel cylinder pressure sensor LH open detection / ERROR or NORMAL	ERROR Momentary interruption NORMAL Normal
      ACC OPN	Accumulator pressure sensor open detection / ERROR or NORMAL	ERROR Momentary interruption NORMAL Normal

   2. Techstream

      ABS / VSC / TR(A)C: 

      ABS/VSC/TR(A)C REFERENCE
      
      

      Item (Display)	Measurement Item / Range (Display)	Normal Condition
      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

      HINT:

      • 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.

   Result: 

   ERROR display does not change. 

   HINT:

   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.

   Fig 2: Identifying Jiggle Connector Or Wire Harness Between ECU And Sensors

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002