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.

1. Turn the power switch OFF and connect the intelligent tester (with CAN VIM) to the DLC3.
   Fig 1: Connecting Intelligent Tester To DLC3

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Turn the power switch ON (IG). Follow the directions on the intelligent tester 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).

   Fig 2: Harness Signal Pattern

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   ABS/VSC/TR(A)C: 

   DATA LIST
   
   

   Item (Display)	Measurement Item / Range (Display)	Normal Condition
   FR SPD OPN	FR speed sensor open detection / ERROR or NORMAL	ERROR: Momentary interruption NORMAL: Normal
   FL SPD OPN	FL speed sensor open detection / ERROR or NORMAL	ERROR: Momentary interruption NORMAL: Normal
   RR SPD OPN	RR speed sensor open detection / ERROR or NORMAL	ERROR: Momentary interruption NORMAL: Normal
   RL SPD OPN	RL speed sensor 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	Acceleration 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	FR wheel cylinder pressure sensor open detection / ERROR or NORMAL	ERROR: Momentary interruption NORMAL: Normal
   FL W/C OPN	FL wheel cylinder pressure sensor open detection / ERROR or NORMAL	ERROR: Momentary interruption NORMAL: Normal
   RR W/C OPN	RR wheel cylinder pressure sensor open detection / ERROR or NORMAL	ERROR: Momentary interruption NORMAL: Normal
   RL W/C OPN	RL wheel cylinder pressure sensor 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

   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 3: Checking Wire Harness Between ECU And Sensors

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002