Open In One Side of CAN Branch Line

NETWORKING: CAN COMMUNICATION SYSTEM: Open in One Side of CAN Branch Line; 2013 MY FR-S [03/2012 -]
- Open in One Side of CAN Branch Line

DESCRIPTION

If an ECU or sensor is not displayed on the CAN Bus Check screen of the Techstream and some ECUs and sensors repeatedly appear and disappear from the screen when the CAN main bus lines are normal (there is no open, short, short to +B or short to GND in the main bus lines), there may be an open circuit in either of one pair of CAN branch lines.

HINT
If some ECUs and sensors repeatedly appear and disappear from the CAN Bus Check screen, communication between the normal ECUs (sensors) and the Techstream may be affected by the incomplete signals that are output from the ECU that has an open circuit in either of its CAN branch lines. In this case, the CAN branch lines for the ECUs and sensors that repeatedly appear and disappear from the screen are normal and the ECU that is not displayed on the screen may be the main cause of the problem (this ECU may have an open circuit in either of its CAN branch lines).





*: for Automatic Transmission System

INSPECTION PROCEDURE

NOTICE:
* Because the order of diagnosis is important to allow correct diagnosis, make sure to begin troubleshooting using How to Proceed with Troubleshooting when CAN communication system related DTCs are output How to Proceed With Troubleshooting.
* After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.
* DTC check procedure: Turn the ignition switch to ON, wait at least 60 seconds,
* After the repair, perform CAN Bus Check and check that all the ECUs and sensors connected to the CAN communication system are displayed Diagnosis System.

HINT
Even after DTCs are cleared, if a DTC is stored again after driving the vehicle for a while, the malfunction may be occurring due to vibration of the vehicle. In such a case, wiggling the ECUs or wire harness while performing the inspection below may help determine the cause of the malfunction.

PROCEDURE

1. CHECK FOR OPEN IN ONE SIDE OF V BUS BRANCH LINE

(a) Based on the vehicle equipment and specifications, confirm the systems that use CAN communication Diagnosis System.

(b) Using the Techstream, select and perform the CAN bus check Diagnosis System.

(c) Observe the screen for approximately 2 minutes to check the ECUs and sensors that are not displayed on the screen and also those that repeatedly appear and disappear from the screen.

(d) Check the applicable communication stop mode for the ECU or sensor that is not displayed on the screen.

NEXT -- GO TO CORRESPONDING COMMUNICATION STOP MODE Symptom Related Diagnostic Procedures