System Description

System Diagram:

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 angle sensor and yaw rate and deceleration sensor.
- The ECM uses the CAN communication system to perform DTC communication instead of the conventional serial 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 an in-vehicle multiplex communication system that 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. Many ECUs (sensors) installed on the vehicle operate by sharing information and communicating with each other.
d. The CAN has two resistors of 120 Ohms which are necessary to communicate with the main bus line.

2. DEFINITION OF TERMS
a. Main bus line
1. The main bus line is a wire harness between the two terminus circuits on the bus (communication line). This is the main bus in the CAN communication system.

b. Sub bus line
1. The sub bus line is a wire harness that diverges from the main bus line to the ECU or sensor.

c. Terminus circuit
1. The terminus circuit is a circuit that is placed to convert communication current of the CAN communication into bus voltage. It consists of a resistor and condenser. Two terminus circuits are necessary for a bus.

d. CAN J/C
1. The CAN J/C is a junction designed for CAN communication, which stores a terminus circuit.

3. ECUs OR SENSORS THAT COMMUNICATE THROUGH CAN COMMUNICATION SYSTEM
a. Skid Control ECU with Actuator
b. Yaw Rate and Deceleration Sensor
c. Steering Angle Sensor
d. ECM

4. DIAGNOSTIC CODE FOR CAN COMMUNICATION SYSTEM
DTCs for the CAN communication system are as follows: U0073/94, U0100/65, U0123/62, U0124/95, U0126/63

5. REMARK FOR TROUBLESHOOTING
a. Trouble in the CAN bus (communication line) can be checked from the DLC3 (except when there is a wire break in lines other than the sub bus line of the DLC3).

NOTE: Do not insert the tester directly into the DLC3 connector. Be sure to use a service wire.

b. The CAN communication system cannot detect trouble in the sub bus line of the DLC3 even though the DLC3 is also connected to the CAN communication system.

6. HOW TO DISTINGUISH THE CAN J/C CONNECTOR
In the CAN communication system, all connectors connected to the CAN J/C are the same shape. The connectors connected to the CAN J/C can be distinguished by the colors of the bus lines.

HINT: See "TERMINALS OF ECU" for bus line colors.