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 Techstream.

1. Turn the engine switch off and connect the Techstream to the DLC3.
2. Turn the engine switch on (IG). Follow the directions on the 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 engine switch is turned on (IG) (initial check).

   Fig 1: Engine Switch Blinking Pattern

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   ABS/VSC/TR(A)C 

   ABS/VSC/TR(A)C NORMAL CONDITION CHART
   
   

   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
   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 Cylinder 2 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.

   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.