Information Bus: Description and Operation

CAN COMMUNICATION: CAN COMMUNICATION SYSTEM: SYSTEM DIAGRAM

1. CAN NO. 1 BUS CIRCUIT









HINT
* The brake actuator assembly (skid control ECU) detects and stores steering angle sensor and yaw rate sensor assembly DTCs and performs DTC communication by receiving information from the steering angle sensor and yaw rate sensor assembly.
* The ECM uses the CAN communication system to perform DTC communication instead of the conventional communication line (SIL).
2. CAN NO. 2 BUS CIRCUIT





CAN COMMUNICATION: CAN COMMUNICATION SYSTEM: SYSTEM DESCRIPTION

1. BRIEF DESCRIPTION

(a) The CAN (Controller Area Network) is a serial data communication system for real time application. It is a vehicle multiplex communication system which has a high communication speed (500 kbps) and the ability to detect malfunctions.

(b) By pairing the CANH and CANL bus lines, the CAN performs communication based on differential voltages.

(c) 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 a wire harness between the 2 termination circuits on the bus (communication line). This is the main bus in the CAN communication system.

(b) Branch wire

(1) The branch wire is a wire harness which diverges from the main wire to an ECU or sensor.

(c) Termination circuit

(1) The termination circuit is a circuit which converts the communication current used in CAN communication into the bus voltage. It consists of a resistor and capacitor. 2 termination circuits are necessary on a bus.

(d) CAN J/C

(1) The CAN J/C is a junction designed for CAN communication, which contains a termination circuit.

3. CIRCUIT DESCRIPTION

(a) In vehicles equipped with the smart key system, the CAN communication system is composed of a main body ECU and 2 bus circuits (CAN No. 1 bus and CAN No. 2 bus), which are controlled by the main body ECU.

(b) The CAN No. 1 bus and CAN No. 2 bus each have termination circuits which use 120 Ohms of resistance, and are capable of high speed communication (500 kbps for the CAN No. 1 bus, and 250 kbps for the CAN No. 2 bus).

4. ECU OR SENSOR WHICH COMMUNICATE VIA CAN COMMUNICATION SYSTEM

(a) Brake actuator assembly (skid control ECU)

(b) Power steering ECU assembly

(c) Steering angle sensor

(d) Yaw rate sensor assembly

(e) ECM

(f) Center airbag sensor assembly

(g) Air conditioning amplifier assembly

(h) Combination meter assembly (combination meter ECU)

(i) Main body ECU (driver side junction block)

(j) 4WD control ECU assembly*1

(k) ECU aggregation box assembly (certification ECU)*2

*1: for 4WD

*2: w/ Smart Key System

5. DIAGNOSTIC CODES FOR CAN COMMUNICATION SYSTEM

(a) DTCs for the CAN communication system are as follows: U0073, U0100, U0122, U0123, U0124, U0126, U0129, B1207, B1499 and B2326.

6. NOTES REGARDING TROUBLESHOOTING

(a) Trouble in the CAN bus (communication line) can be checked through the DLC3 (except when there is a wire break in the branch wire of the DLC3).

NOTICE:
Do not connect the tester directly to the DLC3. Be sure to use a service wire.

(b) DTCs regarding the CAN communication system can be checked using the Techstream.

(c) The CAN communication system cannot detect trouble in the branch line of the DLC3 even though the DLC3 is also connected to the CAN communication system.