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 Techstream.

1. Turn the ignition switch off and connect Techstream to the DLC3.
2. Turn the ignition switch on. Follow the on-screen directions on Techstream to display the Data List and select areas where momentary interruption should be monitored.
   Fig 1: Identifying Blinking Pattern

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   ABS/VSC/TRAC 

   DIAGNOSTIC NOTE
   
   

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   FR Speed Open	Front speed sensor RH open detection/OPN DET or NORMAL	OPN DET, Momentary interruption NORMAL Normal	-
   FL Speed Open	Front speed sensor LH open detection/OPN DET or NORMAL	OPN DET, Momentary interruption NORMAL Normal	-
   RR Speed Open	Rear speed sensor RH open detection/OPN DET or NORMAL	OPN DET, Momentary interruption NORMAL Normal	-
   RL Speed Open	Rear speed sensor LH open detection/OPN DET or NORMAL	OPN DET, Momentary interruption NORMAL. Normal	-

   HINT:

   • A momentary interruption (open circuit) cannot be detected for 3 seconds after the ignition switch is turned on (initial check).
   • If Techstream status remains on, check the continuity between the ECU and the sensors, or between ECUs.
   • The OPN DET display on 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: 

   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.