System Description

NETWORKING: 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, 250 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 using the CAN main wire.

2. DEFINITION OF TERMS

(a) CAN main wire

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

(b) CAN branch wire

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

(c) Termination circuits

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

(d) CAN junction connector

(1) The CAN junction connector is designed so that it can be used with CAN communication which has a termination circuit and CAN communication which does not have a termination circuit.

3. CIRCUIT DESCRIPTION

(a) The V1 bus, V2 bus and MS bus each have termination circuits with resistance of 120 Ohms X 2. High speed communication at 500 kbps and 250 kbps is possible.

4. ECUS OR SENSORS WHICH COMMUNICATE VIA CAN COMMUNICATION SYSTEM

(a) ECM

(b) Brake actuator assembly (skid control ECU)

(c) Combination meter assembly

(d) Center airbag sensor assembly

(e) Air conditioning amplifier assembly

(f) Steering angle sensor

(g) Main body ECU (cowl side junction block LH)

(h) Power steering ECU assembly

(i) Bus buffer ECU*1

(j) 4 wheel drive control ECU (4WD control ECU)*2

(k) Front power seat switch LH (power seat control ECU)*3

(l) Outer mirror control ECU assembly*3

(m) Multiplex tilt and telescopic ECU*3

(n) Suspension control ECU*4

(o) Distance control ECU assembly*5

(p) Power back door unit assembly (power back door ECU)*6

(q) Blind spot monitor sensor LH*7

(r) Blind spot monitor sensor RH*7

(s) Network gateway ECU*8

* *1: w/ Bus buffer ECU

* *2: for 4WD

* *3: w/ Seat Memory

* *4: w/ Air Suspension System

* *5: w/ Dynamic Laser Cruise Control System

* *6: w/ Power Back Door System

* *7: w/ Blind Spot Monitor Sensor

* *8: w/ Network Gateway ECU

5. DIAGNOSTIC CODES FOR CAN COMMUNICATION SYSTEM

(a) DTCs for the CAN communication system are as follows: U0073, U0100, U0104, U0114, U0122, U0123, U0124, U0126, U0129, U0140, U0142, U0155, U0199, U0208, U0230, U0232, U0233, U0235, U1002, U1102, U1101, U1115, U1331, B1499, B2621, B2624 and C1AB8.

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 CAN branch wire of the DLC3).

(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.

7. HOW TO DISTINGUISH CAN J/C CONNECTOR

(a) In the CAN communication system, the shape of all connectors connected to the CAN junction connector is the same. The connectors connected to the CAN junction connector can be distinguished by the colors of the bus line and the connecting side of the connector.

HINT
See "Terminals of ECU" CAN Communication System for bus line color or the type of connecting surface.