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 Telecaster.

1. Turn the ignition switch off and connect Telecaster to the DLC3.
2. Turn the ignition switch on (IG). Follow the directions on Telecaster 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).

   DATA LIST
   
   

   Item	Measurement Item / Range (Display)	Normal Condition
   FR Speed Open	FR speed sensor open detection / OPN DET or NORMAL	OPN DET: Momentary interruption NORMAL: Normal
   FL Speed Open	FL speed sensor open detection / OPN DET or NORMAL	OPN DET: Momentary interruption NORMAL: Normal
   RR Speed Open	RR speed sensor open detection / OPN DET or NORMAL	OPN DET: Momentary interruption NORMAL: Normal
   RL Speed Open	RL speed sensor open detection / OPN DET or NORMAL	OPN DET: Momentary interruption NORMAL: Normal
   EFI Open	EFI communication open detection / OPN DET or NORMAL	OPN DET: Momentary interruption NORMAL: Normal
   Yaw Rate Open	Yaw rate sensor open detection / OPN DET or NORMAL	OPN DET: Momentary interruption NORMAL: Normal
   Deceleration Open	G sensor open detection / OPN DET or NORMAL	OPN DET: Momentary interruption NORMAL: Normal
   Steering Open	Steering sensor open detection / OPN DET or NORMAL	OPN DET: Momentary interruption NORMAL: Normal
   Master Cylinder 1 Open	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 Telecaster remains on for 1 second after the harness signal changes from momentary interruption (open circuit) to normal condition.
     Fig 1: Blinking Pattern

     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.