Check For Intermittent Problems

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 the intelligent tester.

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

Turn the ignition switch on. Follow the on-screen directions on the intelligent tester to display the DATA LIST and select areas where momentary interruption should be monitored.

Fig 2: Intelligent Tester Display Blinking Pattern

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

TESTER DISPLAY NORMAL CONDITION TABLE

Tester Display	Measurement Item/Range	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	-

HINT:

A momentary interruption (open circuit) cannot be detected for 3 seconds after the ignition switch is turned on (initial check).
If the intelligent tester status remains on, 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.

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.