System description

1. 1
   Brief description
2. 2
   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.
3. 3
   By pairing the canh and canl bus lines, the can performs communication based on differential voltages.
4. 4
   Many ecus (sensors) installed on the vehicle operate by sharing information and communicating with each other
5. 5
   The can has 2 resistors of 120 ù which are necessary to communicate with the main wire.
6. 6
   Definition of terms
7. 7
   Main wire
8. 8
   The main wire is a wire harness between the 2 terminus circuits on the bus (communication line). This is the main bus in the can communication system.
9. 9
   Branch wire
10. 10
    The branch wire is a wire harness which diverges from the main wire to an ecu or sensor.
11. 11
    Terminus circuit
12. 12
    The terminus circuit is a circuit which converts the communication current of the can communication into the bus voltage. It consists of a resistor and condenser. 2 Terminus circuits are necessary on a bus.
13. 13
    Can j/c

The can j/c is a junction designed for can communication, which contains a terminus circuit.

1. 1
   Ecu or sensor which communicate via can communication system
2. 2
   Abs and traction actuator (skid control ecu)
3. 3
   Power steering ecu
4. 4
   Steering angle sensor
5. 5
   Yaw rate sensor
6. 6
   Ecm
7. 7
   Center airbag sensor
8. 8
   Air conditioning amplifier
9. 9
   Combination meter ecu
10. 10
    Main body ecu
11. 11
    4Wd control ecu*

*: For 4wd

1. 1
   Diagnostic codes for can communication system
2. 2
   Dtcs for the can communication system are as follows: u0073, u0100, u0105, u0121, u0122, u0123, u0124, u0126, u0129, c1280, c1296, c1297, and b1499.
3. 3
   Notes regarding troubleshooting
4. 4
   Trouble in the can bus (communication line) can be checked through the dlc3 (except when there is a wire break other than in the branch wire of the dlc3).

Do not connect the tester directly to the dlc3 connector. Be sure to use a service wire.

1. 1
   Dtcs regarding the can communication system can be checked using the intelligent tester.
2. 2
   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.