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 (with CAN VIM).

Turn the ignition switch OFF and connect the intelligent tester (with CAN VIM) to the DLC3.

Fig 1: Connecting Intelligent Tester To DLC3
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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.

HINT:

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

Fig 2: Identifying Blinking Pattern

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DIAGNOSTIC NOTE CHART

Item	Momentary Interruption Range (Display)	Normal Condition	Diagnostic Note
SPD SEN FR	Front speed sensor RH open detection / OPEN or NORMAL	OPEN: Momentary interruption	-
SPD SEN FL	Front speed sensor LH open detection / OPEN or NORMAL	OPEN: Momentary interruption	-
SPD SEN RR	Rear speed sensor RH open detection / OPEN or NORMAL	OPEN: Momentary interruption	-
SPD SEN RL	Rear speed sensor LH open detection / OPEN or NORMAL	OPEN: Momentary interruption	-
YAWRATE SEN	Yaw rate sensor open detection / OPEN or NORMAL	OPEN: Momentary interruption	-
DECELE SEN	G sensor open detection / OPEN or NORMAL	OPEN: Momentary interruption	-
STEERING SEN	Steering sensor open detection / OPEN or NORMAL	OPEN: Momentary interruption	-
M/C SEN 1	Master cylinder pressure sensor 1 open detection / OPEN or NORMAL	OPEN: Momentary interruption	-
EFI COM	EFI communication open detection / OPEN or NORMAL	OPEN: Momentary interruption	-

HINT:

If the intelligent tester's status remains open, check the resistance between the ECU and the sensors, or between ECUs.
The OPEN display on the intelligent tester remains on for 1 second after the harness signal changes from momentary interruption (open circuit) to the normal condition.

While observing the screen, gently jiggle the connector or wire harness between the ECU and sensors, or between ECUs.
Result: OPEN display does not change.

HINT:

The connector and / or wire harness has momentary interruption (open circuit) if the display fluctuates. Repair or replace the connector and / or wire harness as one of them is faulty.

Fig 3: Identifying Jiggle Connector
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002