CAN Communication System

CAN COMMUNICATION: CAN COMMUNICATION SYSTEM:

SYSTEM DIAGRAM




HINT:
- The skid control ECU detects and stores steering sensor and yaw rate sensor DTCs and performs DTC communication by receiving information from the steering sensor and yaw rate sensor.
- The ECM, hybrid vehicle control ECU, and battery ECU use the CAN communication system to perform DTC communication instead of the conventional communication line (SIL).

SYSTEM DESCRIPTION

1. BRIEF DESCRIPTION
(a) The CAN (Controller Area Network) is a serial data communication system for real time application. It is a multiplex communication system equipped for a vehicle and has a high communication speed (500 kbps) and a function to detect malfunctions.
(b) By pairing the CANH and CANL bus lines, the CAN performs communication based on differential voltage.
(c) The many ECUs (sensors) installed on the vehicle operate by sharing information and communicating with each other.
(d) The CAN has 2 resistors of 120 Ohms which are necessary to communicate with the main wire.
2. DEFINITION OF TERMS
(a) Main wire
(1) The main wire is the wire harness between the 2 terminus circuits on the bus (communication line). This is the main bus in the CAN communication system.
(b) Branch wire
(1) The branch wire is the wire harness which diverges from the main wire to the ECU or sensor.
(c) Terminus circuit
(1) The terminus circuit is a circuit which is placed to convert communication current of the CAN communication into bus voltage. It consists of a resistor and condenser. 2 terminus circuits are necessary on a bus.
3. ECUS OR SENSORS WHICH COMMUNICATE THROUGH CAN COMMUNICATION SYSTEM
(a) Hybrid Vehicle Control ECU
(b) Battery ECU
(c) ECM
(d) Skid Control ECU
(e) Steering Angle Sensor
(f) Yaw Rate Sensor
(g) Power Steering ECU
(h) Gateway ECU
4. DIAGNOSTIC CODE FOR CAN COMMUNICATION SYSTEM
(a) DTCs for the CAN communication system are as follows: U0123, U0124, U0126, U0293, U0100, U0073, U0111, U0129, U0131, U0146, P3108-594
NOTE: If U0146 or P3108-594 is output, the multiplex communication system may be malfunctioning.

5. REMARKS FOR TROUBLESHOOTING
(a) Trouble in the CAN bus (communication line) can be checked from the DLC3 (except when there is a wire break other than in the branch wire of the DLC3).
NOTE: Do not insert the tester directly into the DLC3 connector. Be sure to use a service wire.

(b) DTCs regarding the CAN communication system can be checked using the Techstream via the CAN VIM.
(c) The CAN communication system cannot detect trouble in the branch wire of the DLC3 even though the DLC3 is also connected to the CAN communication system.