DESCRIPTION

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.

Turn the ignition switch off and connect the Techstream to the DLC3.

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).

Tester Display	Measurement Item / Range	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	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

HINT:

If the Techstream status remains open, check the continuity between the ECU and the sensors, or between ECUs.

Fig 1: Harness Signal And Tester Display Blinking Pattern
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
The OPEN display on the Techstream remains on for 1 second after the harness signal changes from momentary interruption (open circuit) to normal condition.

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

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

Check For Intermittent Problems

Use the Manual With the Right Hardware

When to See a Mechanic

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