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 ignition switch off and connect the intelligent tester to the DLC3.
   Fig 1: Connecting Intelligent Tester To DLC3

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Turn the ignition switch on (IG). Follow the directions on the intelligent tester 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 ignition switch is turned on (IG) (initial check).

   MEASUREMENT ITEM
   
   

   Item	Measurement Item / Range (Display)	Normal Condition	Diagnostic Note
   SPD SEN FR	FR speed sensor open detection / OPN DET or NORMAL	OPN DET: Momentary interruption NORMAL: Normal	-
   SPD SEN FL	FL speed sensor open detection / OPN DET or NORMAL	OPN DET: Momentary interruption NORMAL: Normal	-
   SPD SEN RR	RR speed sensor open detection / OPN DET or NORMAL	OPN DET: Momentary interruption NORMAL: Normal	-
   SPD SEN RL	RL speed sensor open detection / OPN DET or NORMAL	OPN DET: Momentary interruption NORMAL: Normal	-
   EFI COM	EFI communication open detection / OPN DET or NORMAL	OPN DET: Momentary interruption NORMAL: Normal	-
   YAWRATE SEN	Yaw rate sensor open detection / OPN DET or NORMAL	OPN DET: Momentary interruption NORMAL: Normal	-
   DECELE SEN	G sensor open detection / OPN DET or NORMAL	OPN DET: Momentary interruption NORMAL: Normal	-
   STEERING SEN	Steering sensor open detection / OPN DET or NORMAL	OPN DET: Momentary interruption NORMAL: Normal	-
   M/C SEN1	Master Cylinder pressure sensor 1 open detection / OPN DET or NORMAL	OPN DET: Momentary interruption NORMAL: Normal	-

3. Harness Signal.

   HINT:

   • If the status remains on (OPN DET displayed), check the continuity between the ECU and the sensors, or between ECUs.
   • The OPN DET display on the intelligent tester remains on for 1 second after the harness signal changes from momentary interruption (open circuit) to normal condition.
   Fig 2: Identifying Harness Signals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. While observing the screen, gently jiggle the connector or wire harness between the ECU and sensors, or between ECUs.

   Result: 

   OPN DET 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: Identifying Jiggle Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002