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 through the ECU data monitor function of the Techstream.

1. Turn the ignition switch off and connect the Techstream to the DLC3.
2. Turn the ignition switch to ON. Follow the on-screen directions on the Techstream to display the Data List and select areas which should be monitored for momentary interruptions.

   HINT:

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

   DATA LIST REFERENCE
   
   

   Tester Display	Measurement Item / Range	Normal Condition	Diagnostic Note
   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	Deceleration sensor open detection / OPN_DET or NORMAL	OPN_DET : Momentary interruption NORMAL: Normal	-
   Steering Open	Steering angle sensor open detection / OPN_DET or NORMAL	OPN_DET: Momentary interruption NORMAL: Normal	-
   Accumulator Open	Accumulator pressure sensor open detection / OPN_DET or NORMAL	OPN_DET : Momentary interruption NORMAL: Normal	-

   Fig 1: Harness Signal And Tester Display Blinking Pattern

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   HINT:

   • If the Techstream status remains open, 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.

   OK: 

   OPEN-screen display does not change. 

Fig 2: Jiggling Connector Or Wire Harness Between ECU And Sensors

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002