Open in One Side of CAN Branch Line

CAN COMMUNICATION: CAN COMMUNICATION SYSTEM: Open in One Side of CAN Branch Line
- Open in One Side of CAN Branch Line

DESCRIPTION

If some ECUs and sensors are 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 wires are normal (there is no open, short, short to B+, or short to GND in the main bus wires), there may be an open circuit in either of the CAN branch wires.

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 wires. In this case, the CAN branch wires 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 wires).





WIRING DIAGRAM









INSPECTION PROCEDURE

NOTICE:
Before measuring the resistance, leave the vehicle as is for at least 1 minute and do not operate the engine switch, any other switches, or the doors. If any doors need to be opened in order to check connectors, open the doors and leave them open.

PROCEDURE

1. CHECK FOR OPEN IN ONE SIDE OF CAN NO. 1 BUS BRANCH WIRE

(a) Confirm the systems (ECUs and sensors), which use CAN communication, equipped on the vehicle. Diagnosis System

(b) Using the Techstream, select and perform "CAN Bus Check". Diagnosis System

(c) Observe the screen for approximately 1 minute 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) Disconnect the branch wire connectors, which are connected to the ECUs or sensors that never appear on the screen, from the CAN J/C.

































HINT
* *1: w/ Navigation system
* *2: w/ Dynamic radar cruise control system or HID head light type
* *3: w/o Navigation system with multi-display
* Connecting locations of the connectors shown in the above tables are those of a vehicle whose connector locations have never been changed.
* If the connector locations differ from those shown in the above tables, identify each connector according to the color of the bus wires.

(e) Check that the ECUs and sensors, which repeatedly appeared and disappeared from the "CAN Bus Check" screen, are constantly displayed.

(f) Perform the communication stop mode check for the ECUs and sensors which correspond to the disconnected branch wire connectors Diagnosis System.

HINT
If any of the following conditions are met, an open in the CAN bus main wire is suspected. Refer to "Open in CAN Main Bus Line" Open in CAN Main Bus Line.

* Only ECM is not displayed for 1 minute.
* Only combination meter is not displayed for 1 minute.
* All ECUs and sensors connected to the CAN No. 5 J/C are not displayed for 1 minute.

NEXT -- GO TO CORRESPONDING COMMUNICATION STOP MODE