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 engine switch off and connect the intelligent tester or Techstream to the DLC3.
2. Turn the engine 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.
   Fig 1: Engine Switch Blinking Pattern

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   HINT:

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

   1. Intelligent tester

      ABS/VSC/TR (A)C: 

      ITEM DISPLAY
      
      

      Item (Display)	Measurement Item / Range (Display)	Normal Condition	Diagnostic Note
      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	-
      EFI COM OPN	SFI 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/C2 OPN	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: 

      ITEM DISPLAY
      
      

      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	-
      EFI Communication Open	SFI 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.
   Fig 2: Identifying Connector Or Wire Harness Between ECU And Sensors

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   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.