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 by using the ECU DATA LIST function of an intelligent tester.

1. Turn the ignition switch OFF and connect the intelligent tester (with CAN VIM) to the DLC3.
2. Turn the ignition switch ON.
   Fig 1: Connecting Intelligent Tester To DLC3

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3. Follow the prompts on the intelligent tester to display the DATA LIST and select areas where a 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).
   • If the status remains on the ERROR display, check for continuity between the ECU and the sensors, or between ECUs.
   • The ERROR display on the intelligent tester remains on for 1 second after the harness signal changes from a momentary interruption (open circuit) to normal condition.
     Fig 2: Identifying Error Display On The Intelligent Tester

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     ITEM NORMAL CONDITION
     
     

     Item (Display)	Measurement Item / Range (Display)	Normal Condition	Diagnostic Note
     FR SPD OPN	FR speed sensor open detection / ERROR or NORMAL	ERROR: Momentary interruption NORMAL: Normal	-
     FL SPD OPN	FL speed sensor open detection / ERROR or NORMAL	ERROR: Momentary interruption NORMAL: Normal	-
     RR SPD OPN	RR speed sensor open detection / ERROR or NORMAL	ERROR: Momentary interruption NORMAL: Normal	-
     RL SPD OPN	RL speed sensor open detection / ERROR or NORMAL	ERROR: Momentary interruption NORMAL: Normal	-
     EFI COM OPN	EFI communication open detection / ERROR or NORMAL	ERROR: Momentary interruption NORMAL: Normal	-
     YAW RATE OPN	Yaw rate sensor open detection / ERROR or NORMAL	ERROR: Momentary interruption NORMAL: Normal	-
     DECELERAT OPN	Deceleration sensor open detection / ERROR or NORMAL	ERROR: Momentary interruption NORMAL: Normal	-
     STEERING OPN	Steering angle sensor open detection / ERROR or NORMAL	ERROR: Momentary interruption NORMAL: Normal	-
     M/C OPN	Master cylinder pressure sensor open detection / ERROR or NORMAL	ERROR: Momentary interruption NORMAL: Normal	-

4. While observing the screen, gently jiggle the connector or wire harness between the ECU and sensors, or between ECUs.

   OK: ERROR display does not change. 

   HINT:

   The connector and/or wire harness have a momentary interruption (open circuit) if the display changes. Repair or replace the connector and wire harness if either of them is faulty.

   Fig 3: Identifying Jiggle Connector

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