Can Communication System (For Lhd Without Entry And Start System) System Description

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 detection malfunctions.

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

Many ECUs (sensors) installed on the vehicle operate by sharing information and communication with each other.

The CAN has 2 resistors of 120 Ω which are necessary to communicate using the CAN main wire.

CAN main wire

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

CAN branch wire

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

Termination circuits

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

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.
   

The V1 bus, V2 bus MS bus and powertrain bus have termination circuits with a resistance of 120 Ω x 2. High speed communication at 250 kbps and 500 kbps is possible.

ECM

Main body ECU (multiplex network body ECU)

Master cylinder solenoid (skid control ECU)*1

Brake actuator assembly (skid control ECU)*2

Four wheel drive control ECU

Yaw rate sensor assembly

DLC3

Spiral cable sub-assembly (steering angle sensor)*3

Power steering ECU assembly*3

Radio and display receiver assembly*4

Center airbag sensor assembly

Air conditioning amplifier assembly

Network gateway ECU*5

Combination meter assembly

Clearance warning ECU assembly*6

Headlight swivel ECU assembly*7

Driving support switch control ECU*8

Transmission control ECU assembly*9

1. *1: for 1KD-FTV
   
2. *2: for 2TR-FE, 5L-E
   
3. *3: w/ Vehicle Stability Control System
   
4. *4: w/ Audio and Visual System (for Radio and Display Type)
   
5. *5: w/ Network Gateway ECU
   
6. *6: w/ TOYOTA Parking Assist-sensor System (for 4 Sensor Type)
   
7. *7: for LED Headlight
   
8. *8: w/ Multi-function Switch
   
9. *9: for 1KD-FTV and Automatic Transmission
   

DTCs for the CAN communication system are as follows: U0073, U0100, U0101, U0114, U0123, U0124, U0126, U0129, U0131, U0140, U0142, U0151, U0155, U0163, U0164, U0182, U1002, U1110 and U1114.

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).

DTCs regarding the CAN communication system can be checked using the intelligent tester.

The CAN communication system cannot detect trouble in the CAN branch wire of the DLC3 even though the DLC3 is also connected to the CAN communication system.

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" (LandCruiser RM000000XVK0F0X.html) for bus line color or the type of connecting surface.