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 monitor function of the Teachstream.

1. Turn the power switch OFF and connect the Techstream to the DLC3.
2. Turn the power switch ON (READY). Follow the on screen directions on the Teachstream to display the DATA LIST and select areas where momentary interruption should be monitored.

   HINT:

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

   Fig 1: Power Switch Blinking Pattern

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   DIAGNOSTIC CHART
   
   

   Tester Display	Measurement Item / Range	Normal Condition	Diagnostic Note
   SPD SEN FR	FR speed sensor open detection / OPEN or NORMAL	NORMAL: Normal condition	-
   SPD SEN FL	FL speed sensor open detection / OPEN or NORMAL	NORMAL: Normal condition	-
   SPD SEN RR	RR speed sensor open detection / OPEN or NORMAL	NORMAL: Normal condition	-
   SPD SEN RL	RL speed sensor open detection / OPEN or NORMAL	NORMAL: Normal condition	-
   YAWRATE SEN	Yaw rate sensor open detection	NORMAL: Normal condition	-
   DECELE SEN	G sensor open detection	NORMAL: Normal condition	-
   STEERING SEN	Steering sensor open detection	NORMAL: Normal condition	-
   M/C SEN 1	Master cylinder pressure sensor 1 open detection	NORMAL: Normal condition	-
   M/C SEN 2	Master cylinder pressure sensor 1 open detection	NORMAL: Normal condition	-
   STROKE SEN 1	Pedal stroke 1 open	NORMAL: Normal condition	-
   FR W/C SEN	FR wheel cylinder open	NORMAL: Normal condition	-
   FL W/C SEN	FL wheel cylinder open	NORMAL: Normal condition	"-
   RR W/C SEN	RR wheel cylinder open	NORMAL: Normal condition	-
   RL W/C SEN	RL wheel cylinder open	NORMAL: Normal condition	-
   HV COM	HV communication open detection	NORMAL: Normal condition	-
   ACC SEN	Accumulator pressure sensor open detection	NORMAL: Normal condition	-

   HINT:

   • If the status remains on, check the continuity between the ECU and the sensors, or between ECUs.
   • The OPEN display on the Techstream 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: 

   Display does not change. 

   HINT:

   The connector and / or wire harness will have momentary interruptions (open circuit) if the chart fluctuates. Repair or replace connector and / or wire harness as one of them is faulty.

   Fig 2: Checking Continuity Between ECU And Sensors

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002