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 "BUS CHECK" screen of the intelligent tester 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 "BUS CHECK" screen, communication between the normal ECUs (sensors) and intelligent tester 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

PROCEDURE

1. CHECK FOR OPEN IN ONE SIDE OF CAN BRANCH WIRE
(a) Confirm the systems (ECUs and sensors), which use CAN communication, equipped on the vehicle. Diagnosis System

(b) Using the intelligent tester, select and perform "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 are not displayed on the screen, from the CAN J/C.

















HINT:
- 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.
- (*1) : with dynamic laser cruise control system
(e) Check that the ECUs and sensors, which repeatedly appeared and disappeared from the "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.
NEXT -- GO TO CORRESPONDING COMMUNICATION STOP MODE